try going to maaco. I know they are not the best around, but they are the cheapest. And their paints that adhere to plastics are better than thair body paints. They will paint any* vehicle for only $500...total. Here at work, I just designed our box truck to have a full body wrap in bright yellow vinyl (a la my proton, cant get enough yellow) and we wanted the cab to match. It was $500 exactly to paint the entire cab. There was a bit of overspray, but if you take the plates in unattached it should be just fine.

www.maaco.com