What I wanted to do was set up a checkout system where you can choose your price beyond a certain minimum
I have no actual information on how well that will work (it seems like it would), but that phrase triggered a memory for me of an xkcdsucks post:
Radiohead style would be letting people pay however much they want, including nothing. (...) No one cares that you could pay more than a usual price for the album, that's not news. (What! Radiohead will be glad to take money you want to give them! Well stop the presses, mother fuckers!)
I'll try to ignore that bias and evaluate the store neutrally when it's up. This post may be noise.
This is a bit tangential to your point...
No one cares that you could pay more than a usual price for the album, that's not news.
That may well not be true. I doubt that there's an easy route to send small amounts of money to most bands (unlike charities). Here is a tech-savvy author turning away tips from readers, out of fear that they're pirating his books. And he does have free books that might elicit a tip.
This is our monthly thread for collecting these little gems and pearls of wisdom, rationality-related quotes you've seen recently, or had stored in your quotesfile for ages, and which might be handy to link to in one of our discussions.