Free Apps in Mobile Development — What It Is, Models, and How They Work

What Is the Free Model?

Free is a distribution model where the app is available for download and use without monetary payment. Developer revenue comes from alternative sources: ad impressions, in-app purchases, voluntary donations, or selling anonymized user data. The Free model is not a synonym for Freemium — in a pure Free model, there is no paid premium access.

According to Sensor Tower (2025), free apps generate 96% of all global mobile app revenue, although their share of total installs is 97%. The paradox is explained by the fact that even Freemium apps are considered free to download. The pure Free model with monetization only through ads is typical for utilities, simple games, and catalog apps.

The Free model is optimal for: news aggregators (display ads), casual games (rewarded video), apps with high daily activity (flashlights, calculators), and business card apps. The key success factor is high daily audience: the higher the DAU, the higher the revenue at the same ad frequency. According to AppLovin (2025), apps with DAU > 100,000 can be fully profitable through ad integrations alone.

How the Free Model Works in Mobile Apps

The Free model is built on the principle of attention arbitrage: the developer attracts a free audience and monetizes their attention through ads. The model’s effectiveness depends on three parameters: number of active users, usage intensity, and ad eCPM.

User Funnel

In the Free model, the funnel differs from paid: acquisition → install → activation → retention → monetization (ads/IAP). Each funnel stage must be optimized for maximum retention. Retention Rate on D1 (first day) should be > 40%, on D7 > 20%, and on D30 > 10%. With lower rates, a Free app cannot accumulate enough audience to recoup advertising investments in acquisition.

Ad Networks

AdMob (Google), AppLovin, Unity Ads, IronSource, and Meta Audience Network are the largest ad networks for Free apps. Network selection depends on geography, app category, and ad format. Most developers use mediation — connecting multiple networks simultaneously with algorithmic selection of the most profitable ad. According to PubMatic (2025), mediation increases eCPM by 20–40% compared to a single network.

Legal Aspects

The Free model is regulated by privacy laws: GDPR in Europe, CCPA in California, and Federal Law No. 152 in Russia. The app must obtain user consent for data collection for personalized advertising. Without consent, eCPM drops by 50–70% since only contextual ads are available. Consent Management Platform (CMP) libraries like Usercentrics implement consent collection in just a few lines of code.

Main Ways to Monetize Free Apps

The Free model offers several monetization methods. Combining methods (hybrid monetization) significantly increases ARPU.

Display Ads

Display Ads — banners, interstitials, and native ads. Banners have the lowest eCPM ($0.5–$3) but are the least invasive. Interstitial ads show eCPM of $5–$15 and appear between app screens. Native ads are the most eco-friendly format, integrated into the app interface, with eCPM of $3–$10. Each format requires its own placement and frequency to balance revenue and user experience.

Rewarded Video

Rewarded Video — users voluntarily watch a video ad in exchange for an in-game reward: bonus coins, an extra life, or timer acceleration. Rewarded video has the highest eCPM among all formats: $10–$25 in the US and Europe. The voluntary nature of viewing preserves a positive user experience. According to Unity Ads (2025), 65% of mobile game users are willing to watch rewarded video if the reward is valuable for progression.

Donations

Donations — a model where users can voluntarily support the developer. Popular in apps with strong communities: Wikipedia, Brave Browser, meditation apps. The average donation is $2.99–$4.99, and the donor percentage is 1–3% of active users. According to Buy Me a Coffee (2025), apps with donation integration receive an average of $0.12 ARPU per month from donations.

Hybrid Model

Hybrid monetization combines ads with in-app purchases and/or donations. Users can purchase ad removal (remove ads) while staying in the Free model. This increases ARPU: a user who buys remove ads for $4.99 generates revenue equivalent to 500–1000 ad impressions. According to GameAnalytics (2025), hybrid apps show 40% higher ARPU than ad-only apps, with the same Retention Rate.

Ad Monetization of Free Apps

Advertising is the main revenue source for most Free apps. Ad monetization effectiveness is determined by a set of factors that the developer must control.

Ad Formats and eCPM

Ad Frequency and Ad Fatigue

Frequency of ad display critically affects Retention. Interstitials more often than every 60 seconds reduce D7 Retention by 15–20%. Recommendations: interstitials — no more than once every 90–120 seconds, banners — always displayed at the bottom of the screen, rewarded video — only on user request. Ad Fatigue sets in after more than 10 ad contacts per day — after that, users start looking for ad-free alternatives.

A/B Testing of Ads

Testing ad frequency and formats is a mandatory practice. Example of A/B test implementation in Kotlin using Firebase Remote Config:

class AdFrequencyManager(private val remoteConfig: FirebaseRemoteConfig) {
    private val lastAdTime = mutableMapOf<String, Long>()

    fun shouldShowInterstitial(placement: String): Boolean {
        val minInterval = remoteConfig.getLong("ad_interval_ms")
        val lastShown = lastAdTime[placement] ?: Long.MIN_VALUE
        val elapsed = System.currentTimeMillis() - lastShown
        return elapsed >= minInterval
    }

    fun recordAdShown(placement: String) {
        lastAdTime[placement] = System.currentTimeMillis()
    }

    fun getAdGroup(): String {
        return remoteConfig.getString("ad_test_group")
    }
}

Ad Network Mediation

Mediation is a technology that automatically selects the ad network with the highest eCPM for each impression. Connecting three or more networks through a mediation platform (AdMob Mediation, AppLovin MAX, IronSource) is an industry standard. Mediation increases fill rate (percentage of impressions with an available ad) to 95–98% and eCPM by 20–40% (data from PubMatic, 2025).

In-app Purchases: Psychology and Implementation

In-app purchases are purchases within the app available to Free version users. Unlike the Premium model, IAPs exist within a free app and do not require mandatory payment.

Psychology of IAP

The psychology of in-app purchases in Free apps is based on impulse decisions rather than long-term planning. Effective tactics include: offering at the moment of difficulty (running out of lives in a game), limited-time discounts (Promotion with a timer), and social proof (X users have already purchased). According to GameAnalytics (2025), impulse purchases make up 70% of all IAP transactions.

IAP Pricing

IAP pricing in Free apps follows a hierarchy: small (99¢–$1.99, removing the entry barrier), medium ($2.99–$9.99, main revenue), and large ($14.99–$99.99, for whales). Games use consumable IAPs (coins), non-consumable (levels, remove ads), and subscriptions (weekly bonus). The highest conversion rate is for small IAPs priced at 99¢ (12–15% of installs, data from Unity, 2025).

IAP Implementation on Android

Google Play Billing Library provides the API for integrating purchases. Example of IAP initialization in Kotlin:

class IAPManager {
    private lateinit var billingClient: BillingClient

    fun initialize(context: Context) {
        billingClient = BillingClient.newBuilder(context)
            .enablePendingPurchases()
            .setListener { _, purchases ->
                purchases?.forEach { validatePurchase(it) }
            }.build()
        billingClient.startConnection(object : BillingClientStateListener {
            override fun onBillingSetupFinished(result: BillingResult) {
                if (result.responseCode == BillingClient.BillingResponseCode.OK) {
                    querySkuDetails()
                }
            }
            override fun onBillingServiceDisconnected() {
                scheduleRetry()
            }
        })
    }

    private fun querySkuDetails() {
        val params = QueryProductDetailsParams.newBuilder()
            .setProductList(listOf(
                QueryProductDetailsParams.Product.newBuilder()
                    .setProductId("coins_100")
                    .setProductType(BillingClient.ProductType.INAPP)
                    .build()
            )).build()
        billingClient.queryProductDetailsAsync(params) { _, details ->
            updateStoreUI(details)
        }
    }
}

Key Metrics of the Free Model

Managing a Free app requires monitoring ad and user metrics. Without them, it’s impossible to determine whether the model is profitable.

Break-even Point

Break-even is the point where user revenue exceeds the cost of acquisition. For a Free app, the metric looks like this: CPI (Cost Per Install) must be lower than LTV. With a CPI of $1.50 and ARPU of $0.30 per month, the user must stay in the app for at least 5 months. Average CPI in the Games category is $2.80, in Utilities — $1.20 (data from AppsFlyer, 2025).

Ad Revenue Forecasting

Revenue forecasting: Revenue = DAU × Sessions per DAU × Ads per Session × eCPM / 1000. Example: an app with 50,000 DAU, 4 sessions per day, 2 ad impressions per session, and an eCPM of $8 generates: 50,000 × 4 × 2 × $8 / 1000 = $3,200 per day or $96,000 per month. Increasing eCPM to $12 yields $144,000 per month — 50% more without changing the audience.