1. Create a paid application
The first option involves the creation of a mobile application, which can only be accessed by users who make a specific payment for it. You need to create an app that has paid features. This can start already at the transfer stage, to purchases of certain services/functionality within the application itself. Most often, this type is seen in different games.
However, be careful not to exaggerate with high prices. In this case, no one will buy, as there are many free applications on the market. Make sure that the app offers something exceptional, as this is the only way for which the user is willing to deduct their money.