I’ve got some standing orders of 1 or 2 euros every month for bigger projects like grapheneos and kde. And for small apps that I actively use, I try to donate 5 or 10 euros now and then. It’s not much but I believe if everyone is doing their part we succeed in the long run
When ive used a project for a while and i have extra cash I usually do a 20$ donation. Ive been low on money last year so I only donated to a few of the projects, listenbrainz and Lemmy.
Ideally I want to donate a small amount yearly to all the projects I use.