If there is a donation button and its a project, media item, service, etc that I use enough that I would buy it, I often donate. The amount depends on how badly they need the help. If I they try to steer me to recurring donations I don’t donate at all (having the option as an opt-in is okay).

I’m a Buddhist/Atheist. There is far less to fight about here than between Christians/Atheist. I’m sure I’m a “bad” Buddhist too because I take the philosophical bits that make sense to me and leave all the deities and supernatural stuff alone, but Buddhists don’t seem to mind and most atheists don’t either.