Find an Occupational Medicine clinic. They should do it for a low cost. Let them know you'll be a cash pay on the spot and ask to speak to the office manager about a cash pay discount. Another idea would be a chiropractor's office. They frequently have their own x-ray equipment and generally have much lower fee structures than an MD or DO.

I've found that setting up a pay on the spot in cash deal will get you about 2/3 off the "normal" price if it's done right. They would much rather have what they can get now vs dealing with an insurance company that may jack them around.