Review source code and do custom changes to mobile app (android)

The app is a music app, where people can listen to songs. We want to add a feature that limits users usage of the app until they upgrade. Look at the attachment for an example.

So instead of making users pay for a song, we want to display the 'upgrade' message. Or if there is another way you can add the message this is fine. You will need to integrate it with Stripe and PayPal. You will alsoneed to make a way of telling the backend system that the user has upgraded, so he or she will no longer have to pay to listen to any songs, and they won't see the old upgrade pop up message anymore.

This is an ongoing project, with custom work being needed every month. We also have a website so if you can develop websites also that would be great.

A commission bonus of 5% of the project fee will be paid upon successful completion.