Payment method when I have more tan 1.000 possible users for an App

At the moment I’m creating an app that could be used by more than 1.000 users of more than 10 factories.
How should I deploy the app and in which payment method ?
Becaus the purpose is not to pay for the whole 1.000 people because it would be e really expensive

Thank you in advice

The data that belong to 10 factories are sensitive in nature?