In-App-Purchases iOS
Notes and resources:
- https://www.theverge.com/21445923/platform-fees-apps-games-business-marketplace-apple-google
- https://developer.apple.com/app-store/small-business-program/
- https://support.google.com/googleplay/android-developer/answer/112622?hl=en
- https://support.google.com/googleplay/android-developer/answer/10632485