Showing examples of all in-app purchases using the latest Google Play Billing Library. The app has covered the following functionality. 1: Multiple subscriptions. 2: One-time purchase (Non-Consumable purchase). 3: Unlimited purchases (Consumable purchases). 5: Remove Ads purchase (Admob and Facebook) 6: Restore owned purchase button. 7: Auto subscription check and activate 8: [New] Subscription Upgrade and Downgrade 9: [New] Store and read coins and subscriptions from Firebase Special features: Able to increase Quantity. Has Price offer.