I've paid as little as $200 and as much as $1000 to do a frame, axle and suspension, core support and inner fenderwells. I've had friends pay much more when they use colors or want perfection. Most production shops should have a booth big enough. You can save some money by sandblasting the frame yourself and also by deciding if you need a perfect show finish or can get by with a couple thin spots here and there. Also some production shops might be able to group it with others getting the same color, so check with places like bumper manufacturers in your area. My old local powdercoater did the mailboxes for the USPS, so if you wanted a frame blue, it was like $100. Oh yeah, my biggest regret is not powdercoating my frame on my truck.