Graffiti as a business.?

Ive heard of a few places trying this out; i dont know how well it does but depending on how much graffiti is in your city it might be a good thing. You can either charge money at the entrance OR you can sell paint/art supplies or both. Some places ive been to let you paint for free but you got to buy the paint from them- inside they sell paint, markers, tshirts etc