This is some time past the original post, but in case anyone else starts searching for the same information, I figured I'd answer it here.
You didn't mention which model number oven you had, but assuming it's one of the parts that we carry on our site, the part is under $100. If you have to pay someone to do your repair, of course you'll have to pay labor. But if you can do the repair yourself, it should be pretty reasonable.
Hope that's helpful to anyone else who looks for this info in the future.