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
In Germay / Europe we have a good banking system where oftentimes you don’t pay for the transaction. You just need an IBAN.
Giving money to stripe or paypal seems to be nuts, imo.