Imagine you created your very first app. You developed the concept, workedtirelessly on the key features, design, tested it and fixed the bugs. Themoment has...
i am good with the subscription and pay once approaches they mentioned.
the iffy portion is the in-app payment sdk. i hope f-droid will be the one providing those to have it standardized.
in-app ads are kinda okay. i won't use said app, but if f-droid labels apps like those as how it labels apps with non-foss/features-you-may-not-like, it should be okay.
In app ads are very much not ok as they are often targeted and serve no benefit to the user. I have no issue with a donate button popup with a link but we already have Google play for spyware.