- App purchases: Developers charging for applications and downloads from Google Play must do so by using Google Play's payment system.
- In-app purchases: Developers offering additional content, services or functionality within an application downloaded from Google Play must use Google Play's payment system as the method of payment, except:
. where payment is primarily for physical goods or services (e.g. buying movie tickets; e.g. buying a publication where the price also includes a hard copy subscription); or
. where payment is for digital content or goods that may be consumed outside of the application itself (e.g. buying songs that can be played on other music players)
Does that mean I cannot use any 3rd party payment system?
It depends on your app.. if your selling movie tickets as below, then you are fine.
You also could make different versions of the app with payment system for different markets, but that can be a headache.
depending on the interpretation of "were payment is for digital content or goods that may be consumed outside of the application itself (e.g. buying songs that can be played on other music players)" You could arguably make a free app that uses stripe to sell other apps, but I am not a lawyer, and this is not legal advice, and even if legal, that won't mean google won't boot such an app.