Economy design in simulation games is the invisible skeleton most players never consciously notice but the difference between dropping a game after two hours and opening it three days in a row. It's what keeps Stardew Valley going past midnight, and what causes Recettear to be quietly closed after the first week. Economy is not just "how much gold"; it's the frame around the answer to the question every player asks each minute: "what should I do now?"
At Althera Games, this is exactly what we wrestle with on Potion Rise Simulator: a four-stage production chain from seed to potion, a customer base that runs from common townsfolk to nobility, and a reputation that shifts with every dialogue choice. In this post we share the principles we lean on when designing a sim economy, the traps we work to avoid, and the small adjustments that make a player say "one more round."
The Core Components of a Sim Economy
A sim game's economy is the interplay of three core components: resources, transformations, and scarcity. Resources are the inputs the player holds (seeds, raw materials, money, time, energy). Transformations are the mechanics that convert one resource into another (growing a plant, extracting essence, mixing a potion, selling). Scarcity is the rule that limits when transformations are possible (day length, inventory, NPC demand, skill level).
The right ratio between these three gives the game its rhythm. In Stardew Valley, seed (resource), growth time (transformation) and the energy bar (scarcity) combine to make "what do I plant this morning" a real decision. In Travellers Rest, drink production (transformation), customer flow (scarcity) and barrel capacity (resource) form the same kind of equation.
In Potion Rise Simulator the triad is built like this:
- Resources: Seeds, water, light, experience, gold, NPC relationships, and lab equipment.
- Transformations: Seed → plant, plant → extract, extract → potion, potion → sale. Each stage demands different skills and time.
- Scarcity: Field bed count, limited still capacity for extraction, the daily count of arriving NPCs and what they actually order.
This structure ensures every session presents a fresh "what first" decision. If three noble orders came in today, do you save your current extracts for them, or sell to common townsfolk at the market for instant cash to buy more seeds? That is what economy is: not numbers, but decisions.
Money Flow: Income and Expense Curves
The most concrete face of economy design is money flow — gold in and gold out. Most indie sim games design this flow either too generously or too tightly. Both end the same way: the player gets bored.
A healthy flow works like this: the player generates income at a certain rate, but not all of it goes into savings. There are necessary outflows — what designers call money sinks. Seed re-buying in Stardew Valley, equipment repair costs in Graveyard Keeper, and ingredient restocking in Travellers Rest are textbook money sinks. Without them an economy bloats and money loses meaning.
In Potion Rise the planned money sinks include:
- Seed renewal: Some plants are single-harvest, some are multi-harvest. Single-harvest crops are more profitable but require constant repurchasing.
- Equipment maintenance: Stills, mortars, and ovens lose performance after a certain number of uses; repair or replacement creates outflow.
- Home and furniture: Cosmetic but important. A place where the player feels "I can see the gold I've earned."
- Guild dues and certifications: Reaching noble customers requires guild membership; in late game, this is a major sink.
The linear vs exponential curve question is critical too. A linear earnings curve bores players; making the same gold every hour grows monotonous fast. An exponential curve burns the player out quickly and makes late-game gold meaningless. The sweet spot is a logarithmic curve: rapid rise in early game, steady growth in mid game, a slowing late game refreshed by new objectives. Recettear dramatized this perfectly through its weekly debt deadlines.
A good sim economy keeps the player permanently on the edge of "if I earn just a bit more, I can buy that thing." When that threshold is crossed, a new threshold appears immediately. When the economy stops, the game stops.
Scarcity vs Abundance: The Driving Dynamic
How rich a game feels is not measured by total gold but by the amount of stuff the player wants but can't easily obtain. This is the scarcity-abundance dynamic, and it is the heart of every sim game.
Abundance feels rewarding after long stretches of effort; but if abundance comes too early, motivation collapses. Conversely, if scarcity is too harsh, the player burns out. The designer's job is to ensure neither pole dominates for too long.
Several main mechanisms drive scarcity-abundance dynamics:
- Time scarcity: A day has a fixed number of hours; the player can't do everything. Stardew Valley's primary engine.
- Space scarcity: Field, storage, or inventory is limited. Moonlighter's inventory optimization is the pure form of this principle.
- Knowledge scarcity: The player doesn't know what each NPC wants or what each recipe does at first. Potion Craft's recipe discovery on the alchemical map is a beautiful example.
- Social scarcity: Reaching certain NPCs requires reputation or completed quests. Potion Rise's noble class is locked exactly along this logic.
Abundance moments are also necessary. Harvest day, a strong end-of-day report, a satisfied compliment from a noble customer — these signal "you're doing well" to the player. The key equation: scarcity pressure keeps the player engaged, abundance moments keep them happy. Pure scarcity creates stress; pure abundance creates boredom.
Progression Curves: Early, Mid, Late Game
Sim games are long by nature. 20-40 hour average playtimes are normal. An experience this long should be split into three distinct economic phases: early, mid, and late game. Each phase should have its own dynamic, its own goal, and its own reward system.
Early game (0-3 hours): Learning and warm-up. The player is getting to know the core loop, the UI, and the main mechanics. Money is unimportant in absolute terms but every reward feels huge. The first potion sold, the first harvest, the first customer review — these are the early-game engines. In Potion Rise this phase begins with common townsfolk customers, a handful of seeds, and a single still.
Mid game (3-15 hours): Expansion and specialization. The player knows the loop and now wants to optimize. New systems must open in this phase: new recipes, new NPC classes, new locations. In Potion Rise's mid game, artisan and clerical NPCs come into play; they place more complex orders but pay better. The reputation system becomes a critical engine in this phase.
Late game (15+ hours): Mastery and prestige. The player has now broken the basic economy. Status, collection, and rare rewards take over. Noble-class NPCs, royal commissions, and legendary recipes are the late-game fuel. Travellers Rest opens chain expansion and dedicated customer routes in late game; a similar logic can be built into alchemy sims through guild ranks and city-wide prestige.
Transitions between the three phases must be smooth. A hard paywall or a level wall pushes the player away from the screen. The natural transition uses nested objectives: while completing a recipe, the player meets a new NPC, who hands a new quest, which unlocks a new mechanic.
Pacing and Soft Caps
Pacing is the control over how fast a player advances through the economy. A good sim economy grows continuously without exploding in the player's face. One of the strongest tools to maintain this control is the soft cap.
A soft cap is the invisible ceiling beyond which progress slows down. Unlike a hard cap, it doesn't forbid; advancement continues but no longer at the same pace. For example, in Stardew Valley you can grow a single-crop farm without limit, but past a certain point, watering and harvest time eat into the profit gain — a soft ceiling forms in practice.
What soft caps add to a sim economy:
- Natural slowdown: The player slows down without noticing and starts looking for new strategies.
- Decision pressure: "Doing more of the same thing" becomes less efficient than "trying something different."
- Horizontal growth incentive: The player diversifies the portfolio rather than anchoring on a single income channel.
In Potion Rise the soft cap idea is implemented like this: selling too many of the same potion saturates the market and lowers the price; selling repeatedly to the same NPC reduces reputation gain; over-planting the same seed reduces soil yield (quality drops in subsequent harvests). None of these forbid the player; they just make diversity more profitable. Mark Brown's analyses on pacing across genres on his Game Maker's Toolkit channel illustrate this principle nicely.
Social Economy: NPC Economies and Reputation
Numbers alone don't make an economy; turning the economy social is one of the strongest tools to keep a player engaged. When NPCs are not just sales nodes but stories, every selling decision carries emotional weight.
Recettear discovered this early: the haggling mechanic was an economy optimization, but once the same NPC visited weekly, had a personality, and had a story, that haggling became unforgettable. Stardew Valley's NPC calendars, birthdays, and gift preferences pulled the economy out of pure money loops and into a social loop.
In Potion Rise the NPC economy splits into the following classes:
- Common folk: Low pay, frequent visits, simple demands. The bread-and-butter layer.
- Artisans and craftspeople: Mid pay, specific demands. Repeat customers for certain potions.
- Officials and officers: High pay, fewer visits, prestige-bearing demands.
- Noble class: Very high pay, rare visits, unique and demanding orders. Locked behind reputation gates.
This class hierarchy is also tied to a dialogue and ethics system. The player can make "good" or "evil" choices on each order: selling fake potions, inflating prices, hiding the truth. These choices earn money in the short term but erode reputation in the long term. In Potion Rise, the door to the noble class isn't opened by gold alone but by a reputation built on honesty and quality. This adds depth derived from character development to the economy itself.
When designing reputation systems, watch for: giving the player a visible measure (a number, a badge, an NPC reaction), making decline possible but recoverable, and tracking different reputations for different classes. In Potion Rise, a player with high noble reputation cannot have warm relations with the black market simultaneously; this opens a natural specialization path within the economy.
Testing and Data: How to Balance an Economy
The hardest part of designing an economy isn't the design but the balancing. A system that looks great on paper can collapse three hours into actual play. That's why every sim economy needs a spreadsheet-based balance document.
The basic columns we use for Potion Rise:
- Item name, category, unlock hour (in game hours)
- Input costs: seeds, water, equipment, time
- Production duration (in in-game days)
- Output: base sale price, common price, noble price
- Profit margin and profit per minute (PPM)
- Required skill level and reputation
- Money sink impact (where applicable)
From this table we plot the curve of "maximum gold the player can stack at hour X." The curve must be logarithmic; if it comes out linear or exponential, we re-tune prices, production durations, and unlock timing.
Daniel Cook's economy design essays on the Lost Garden blog are extremely practical for spotting "competing" economic loops; in particular, the parts that flag the risk of one mechanic resetting another are required reading for sim designers.
The spreadsheet is just the beginning. Real balance comes from playtests. While testing, we watch for these signals:
- How much passive money is the player accumulating? Too much accumulation means money sinks are missing.
- Which item is the player producing the most? If there's only one profitable spot, the others need tuning.
- Which NPC class is being skipped? If a class isn't worth visiting, its rewards need reconsideration.
- Where's the first dropout point? This is almost always a pacing problem.
Applying these methods during a Steam Early Access window is especially powerful; tuning balance against live player behavior grows both the game and the community. We covered that loop in detail in our Steam Early Access guide.
Frequently Asked Questions
How hard should the early game be?
The early game should challenge the player without breaking them. The goal in the first 30-60 minutes is for the player to learn the core loop, taste a small win, and clearly see the next objective. Difficulty should come not from raw money pressure but from decision pressure: every seed, every customer, every potion recipe should force a "now or later" choice. In alchemy sims like Potion Rise, unlocking all recipes within the first hours flattens the economy; gating recipes and starting with common-class customers builds a natural warm-up ramp.
How much RNG should you use?
RNG keeps an economy alive but irritates players when it's unbounded. A good rule: random in the short term, deterministic in the long term. A ±20% variance on a plant's extract yield is exciting; if a player still hasn't hit the average after 10 attempts, the system feels broken. Pity systems, weighted distributions, and guaranteed minimums keep RNG fair. For noble NPC orders, demand drawn from a curated pool feels far more satisfying than fully random demand.
Are soft economy resets necessary?
For long-form sim games, soft resets are nearly mandatory. After 20 hours, the player can afford everything and motivation collapses. The fix is opening a new tier: a new town, a new NPC class, new raw materials, or a new investment target (lab expansion, royal certification). This devalues existing money without erasing the player's effort. Stardew Valley's Ginger Island is a textbook example.
How do you build an economy spreadsheet?
For each item, the row should include: input cost, production time, sale price, profit margin, profit per minute, required skill level. Combine these with unlock timing and plot a curve of "maximum money the player can earn at hour X". The target curve should be logarithmic: steep early, flattening late. Excel or Google Sheets is enough; you don't need fancy tools. The real work is reviewing the curve by eye and marking the points where the player would lose interest.
Is gifting the player money harmful?
Money given without context is harmful; money given with narrative weight is powerful. A quest reward, an NPC tip, or a found treasure chest folds into the player's story and motivates them. But 100 free gold dropped into the bag every morning erodes the value of the whole economy. Practical rule: a gift should not exceed 10-20% of an hour's active earnings, and it must have a narrative reason. In Potion Rise, a noble NPC handing over a rare seed lands far stronger than a pile of coins.
Conclusion: Invisible but Decisive
A good sim economy is a skeleton the player never directly notices; but without that skeleton, no game survives long sessions. At every step of seed → plant → extract → potion the player makes a decision: how to use time, who to sell to, which reputation to chase. What makes those decisions meaningful is the economy design itself.
At Althera Games, we measure, test, and re-tune these principles daily on Potion Rise Simulator. The iteration speed UE5 gives us is gold for testing numerical systems like an economy — we wrote about that engine choice in detail in building indie games with UE5.
If you're designing a sim game, put your spreadsheet front and center. Then play the game. If the numbers don't speak, the game won't either.