Monetizing Android apps requires choosing the right strategy for your audience and app type. In-app purchases remain the most profitable model, generating over 70% of Google Play revenue. Offer consumable items for games, non-consumable for premium features, and subscriptions for ongoing content. Implement Google Play Billing Library for secure transactions. Ad-based monetization works well for utility apps with high engagement. Integrate AdMob for banner, interstitial, and rewarded video ads. Balance ad frequency to avoid user churn. Freemium models offer basic features free with premium upgrades. Subscription models provide recurring revenue through Google Play's subscription system. Consider implementing introductory pricing and promotional codes. Affiliate marketing integrates product recommendations within your app. Sponsorships work for apps with niche, engaged audiences. Data monetization should be approached carefully with user consent. Implement A/B testing to rates. Use Firebase analytics to track user behavior and identify monetization opportunities. Consider offering lifetime purchase options alongside subscriptions. Localize pricing for different markets. Remember that user experience should never be sacrificed for revenue.