a have a friend who paints awesome line drawing goofiness. she went crazy painting one summer and so we made her get a booth at a city summer fest because she had so damn many. her idea was to make the paintings sized so you could put them in your cargo pocket and walk off with your treasure. she charged like 30-40 bucks....because, hell its art, man. and she wanted people to appreciate it. if no one wanted to buy them (paying her for her cool brain, her time and her talent) then she would enjoy them herself....
moral of the story: if people want it, they should pay you for your time, your heart and your labor.

and you rock.