Maybe I just don't know how these things work, but... is Patreon not an option? Or something similarly simple?
I have to look into them. I assume they take a cut, do you know how much? As these things are fairly easy to implement, I don't know if Patreon adds value equivalent to what they take.
As far as I know, Patreon is like an indefinite Kickstarter for artists. A quick look takes me to this page: https://patreon.zendesk.com/hc/en-us/articles/204606125-How-do-you-calculate-fees- which says they take 5%, plus they mention other fees that might apply.