I simply leave it up to people to decide if they want to donate and if so how much.
Donations are always nice as they show appreciation but the stacks are free and I wouldn’t want to insinuate anything other than this with a suggested amount.
All support is also free and I would never want people to think that they had to donate in order to get help.
Don’t forget that the Background child stack (as used by BluePrint and Sections Box etc) allows you to paste in gradients from generator sites such as the one that @webdeer mentioned (there a quite a few other nice ones out there as well).
Just select Paste Gradient from generator as the background type.
Where would I be without my BluePrint Sidebar, a very useful valuable stack and if you haven’t add it to your stack collection then what are you standing around for??? Head over to BWD page and download it
Be sure to send a coffee or two donation over to @tav for this awesome stack so he can stay up all night developing more stacks for us