1.  In App Purchases In-app purchasing refers to buying goods and services from inside an application on a mobile device, such as a smartphone or tablet. 2. What kind of IAP are (consumable, non-consumable, auto-renewable, and non-renewing subscriptions. 2. How to Implement Google In-App Billing (with some code snippets ) Here, we can talk about the steps of implementation, the listeners of google billing, after getting a google play subscription response how to validate with your back-end(which makes your application billing system secure) 3. Google billing frequency. 4. After finishing the subscription period, what will Google play(grace, on hold). [h2][b][url=https://docs.google.com/presentation/d/15ixQSlSo5SXll4riDK7S6WUWxkSvkBS-t-K8sTVeLgk/edit?usp=sharing]Slides[/url][/b][/h2]