GeoWeather One-Time Payments adding with different Plans

If I would add One-Time Payments (there would still be a free plan) with optional login (after login the Plans would be displayed and until then there is only the free plan to choose) into GeoWeather how would it look? Like would there be any more like it would be no longer be updated or something in that direction?

How are these implemented in a FLOSS way?

I am working on my own API for the Login and Subscription prices but for payments I would need to look.

do you know any payment gateway/provider that is FLOSS?

For your website? Surely Stripe has something, not FLOSS I guess.

For in-app? Not that I know, maybe Taler when ready…

Its in-app but via the api

I will make the payments via the Crypto Wallet -To-Wallet flow