How to design a game economy that supports IAP, hybrid, and D2C transactions

What is game economy design?

Game economy design is the practice of building the systems that govern how currencies, resources, and items work together in a game. In free-to-play games, particularly for games that use in-app purchases or a hybrid monetization model, the game economy is a primary revenue driver. A well-designed free-to-play economy paces progression, gives free players a reason to come back tomorrow, and creates non-coercive moments where spending money or watching an ad feels like a good trade rather than disruptive or forced.

Economy design sits at the intersection of retention and monetization: every free-to-play game, whether it earns through in-app purchases (IAP), ads, or a hybrid mix of both, is built on top of an economy. The 2026 Unity Game Development Report found that for a majority of respondents in-app purchases drive their monetization - and 29% of respondents report they’re shifting toward diversified business models rather than single-lever revenue. For most free-to-play games that rely on IAP and hybrid monetization, the game economy is foundational.

Key takeaways

• The economy is the business model: In free-to-play, nobody pays to install. Currencies, faucets, sinks, and converters are what actually generate revenue and keep players coming back.
• Segment players: Non-payers and payers each need the economy to work differently. Roughly 5% of players roughly drive over 50% of in-game purchase revenue*, but designing only for that tier can break the gameplay experience.
• D2C adds new design needs but doesn’t change fundamentals: A working web shop needs a single server-side currency ledger, pricing gaps that are intentional and disclosed, and cosmetic sinks that are exclusive to the web store.
• Genre sets economy depth: Hypercasual runs almost entirely on ads, while RPG/strategy leans 60–80% IAP, and hybrid-casual sits in the middle. Each requires different economy tuning.
• Model player time and spending: Price curves for upgrades and boosts should form an S-curve with fast early progress to build investment, and a steady predictable rhythm after increasing difficulty.
• Use combined health metrics to diagnose problems: Inflation rate, currency velocity, sink-to-faucet ratio, days-of-currency-on-hand, payer conversion rate, and ARPPU together tell you whether a problem is too many faucets, too few sinks, or too few payers.

Core game economy components

Every game economy is built from four basic parts: currencies, faucets, sinks, and converters.

Currencies (soft & hard)

Soft currency is usually earned through play and comes in the form of coins, gold, or energy. Hard currency is scarce and is typically tied to real money and is represented by gems, diamonds, and crystals. Most free-to-play games run at least a dual-currency system so that free players always have something to earn while paying players have something worth buying. Typically most in-game transactions are priced using soft currency, with hard currency being used to purchase more soft currency than can be earned through faucets.

Faucets (sources of currency)

Faucets are how players can earn currency and control the pace of progression. Faucets usually pay out in soft currency. Some examples include level completions, daily login bonuses, quests, achievements, and, in ad-supported and hybrid games, reward video ads. Rewarded ads have become one of the most important faucets in modern mobile economies. If rewarded ads are clearly valuable to the player, it doesn't just generate ad revenue - data from Unity's own opt-in offerwall rewards placements shows engaged players sticking around at nearly four times the rate at two weeks and almost five times the rate at two months compared to players who never engage with them.

Sinks (currency drains)

Sinks are where and what players spend currency in the system. Examples include purchases, removing ads, cosmetics, and entry fees. Sinks are what keep currency meaningful. Without enough of them, players stockpile rewards until nothing feels worth earning or buying. Difficulty spikes, sometimes called pressure points, are a common tactic to leverage game progression to drive sink efficacy.

Converters (exchange between currencies)

Converters bridge the free and paid sides of the economy. Players can exchange hard for soft currency or time for currency through a rewarded ad view that yields a slice of premium currency. The design challenge is setting the exchange rate so the ad-earned reward samples the premium experience without fully replacing it.

Designing a dual-currency system for hybrid monetization

In the standard free-to-play model, soft currency handles routine spending (upgrades, retries, small boosts), while hard currency gates premium content, like cosmetics and removing ads. Hard currency is either purchased directly through IAP or earned in deliberately small amounts through play or rewarded ads.

The core question to answer is the exchange rate: at what ratio should players be able to convert hard currency to soft? Get this wrong in either direction and one currency cannibalizes the other. Either players never need to spend real money because soft currency and rewarded ads cover everything, or hard currency becomes so tightly gated that free players feel forced to spend during difficulty spikes.

In hybrid games, which make up the majority of free-to-play games, this is why the monetization levers of IAP and ads need to be designed together rather than bolted on separately. A common framework segments the player base by behavior rather than by feature: non-payers are monetized fully through ads, micro-payers respond to well-timed rewarded placements tied to specific purchases, and high-value payers get an ad experience that barely touches them at all**. Segmenting this way protects your best-paying players from ad fatigue while still turning your ad-watching majority into revenue.

This logic underpins the classic free-to-play payer pyramid: non-payers, minnows (occasional small spenders), dolphins (regular moderate spenders), and whales (a small group of high spenders).

Roughly 5% of players account for over 50% of in-game purchase revenue spending in a typical free-to-play title - in some mobile game titles, the 1% of top spenders can generate up to 30% of total revenue***. The economy has to work for all four groups at once: non-payers and minnows need faucets and sinks that make the free game genuinely satisfying on its own as they're the ones generating ad revenue, while dolphins and whales need hard-currency sinks deep and desirable enough to be worth repeat spending.

Designing your economy to support D2C transactions

Direct-to-consumer (D2C) monetization means selling currency and items to players through a developer-owned webshop instead of exclusively through the App Store or Google Play. The appeal is clear, as app store fees can typically run 15–30% per transaction, and routing even a portion of purchases through a D2C storefront can lift net margin.

Regulatory shifts have made external payment links and web shops more viable across more regions, though the US position is still being litigated and could change****. A D2C channel doesn't change the currencies, faucets, sinks, and converters your economy needs - but it adds new design and UI requirements on top:

• A single server-side currency ledger: Hard currency balances need to live on the player's account rather than being tied to a specific store or device, so a purchase made on the web shows up instantly in the game and vice versa. This is exactly the architecture dedicated D2C infrastructure is built around: Unity's IAP SDK, for example, connects native app stores and a webshop through one unified catalog so a player's inventory and spend stay in sync across both channels rather than living in two separate systems.
• Clearly advertise pricing incentives: Ensure that webshop discounts are visible and clearly advertised as promotional. Because a web shop skips the roughly 15-30% platform fee, a recommendation is to price web-exclusive offers differently from the in-app store rather than mirroring it, since the savings can be passed on as better value. But if webshop discounts aren’t clearly marked as intentional incentives, then players may resent the price gap between the in-game and online marketplaces.
• Keep webshop exclusive content cosmetic: The strongest D2C economies don't just mirror the in-app shop online*****. They add bundles or rewards that exist only in the web store, giving players a genuine reason to go off-platform. Some studios go further and build a loop where in-game activity earns points redeemable in the web shop and web purchases unlock in-game perks, turning the storefront into an extension of the core loop rather than a separate transaction page. Either way, try and keep webshop exclusives cosmetic - exclusives that affect gameplay can lead to some players feeling like the game is introducing pay-to-win mechanics.

Price curves and progression

Upgrade and unlock costs should scale so that early progress feels fast and later progress feels earned. The goal is to model the exchange rate for player time, not just currency: how long should a free player need to grind for an upgrade or boost, versus how much hard currency would skip that wait?

A useful way to think about this is to build a few player scenarios in a spreadsheet and use them to plot how long each type of player takes to reach each milestone. Reward tiers should unlock quickly at first to build early emotional investment, then settle into a steady, predictable rhythm. For example, one meaningful reward roughly once a day for an engaged player, stretching to once every two or three days for a casual one. Plotted on a graph, the thresholds should form an S-curve rather than a straight line, as strictly linear progression can feel either too easy at the end or too grindy at the start.

Game economy health metrics

Inflation rate: The rate at which the total amount of currency in an economy grows over a given period, measured as the difference between currency entering (faucets) and currency leaving (sinks).

Currency velocity: The rate at which currency changes hands or is spent within a given period, measured as how quickly earned currency moves from a player's balance back into the economy through spending.

Sink-to-faucet ratio: The ratio of total currency removed from the economy (sinks) to total currency introduced into it (faucets) over a given period or progression tier.

Days-of-currency-on-hand: The average amount of unspent currency a player holds, expressed as the number of days of typical earning it would take to accumulate that balance.

Payer conversion rate: The percentage of a game's total player base that makes at least one purchase within a given period.

ARPPU (average revenue per paying user): The average amount of revenue generated per paying player over a given period, calculated as total revenue divided by the number of paying players.

Pulling these numbers from live analytics is what enables you to steer your economy. Tools like Unity Analytics are built to surface exactly this kind of player-level economy data.

Getting started

1. Map your core loop and identify every point where currency enters and exits.

2. Choose your currency types - start with a simple dual-currency system.

3. Build a spreadsheet model to project currency flow over 30/60/90 days across a few player scenarios (casual, engaged, and a theoretical ceiling case).

4. Set sink-to-faucet targets for each progression tier and test them with playtesters.

5. Connect your economy to your monetization plan. Decide up front how currencies are earned through play, which are purchased, and which are ad-based.

6. Track economy health metrics post-launch and be willing to adjust. Remember, it's far easier to loosen an economy that's too tight than to tighten one that's already too loose.

Ready to put your monetization plan into action? Monetize your game with Unity.

*https://sqmagazine.co.uk/in-game-purchases-statistics/

**https://audiencelab.ai/blog/mobile-game-monetization-strategies

***https://sqmagazine.co.uk/in-game-purchases-statistics/

****EU: Digital Markets Act, Regulation (EU) 2022/1925. Japan: Mobile Software Competition Act (effective Dec. 2025). South Korea: Telecommunications Business Act, as amended (2021). US: Epic Games, Inc. v. Apple Inc., 147 F.4th 917 (9th Cir. 2025), cert. granted (U.S. June 30, 2026); In re Google Play Store Antitrust Litigation, No. 3:21-md-02981 (N.D. Cal.), joint motion to modify withdrawn July 15, 2026.

*****https://www.stash.gg/blog/supercell-store