So, is there a rule of thumb? An expected percentage of a sale? A minimum? If you have to ask, you can't afford it?
And how do you go about it? Maybe there should be a button that opens a "Contributions" page with instructions. If it were easier, maybe there would be more contributions from people who don't sell anything and just want to help support the site. (It's possible!)
Is it inappropriate to ask here?
Just wondering.











