All taxidermists are expensive, if it was easy and cheap, everyone would be doing it. Seriously, the cheap ones if you find one will probably disappoint you. Go to different taxidermists and look at their work, then choose the one you think is best. Who wants an almost good mount.
What WW said. With a few exceptions, you usually get what you pay for. For turkeys, I'll recommend Outback Imagery in York Springs, PA. It's probably on the outer edges of your specified distance, but every turkey mount that I've seen come out of his shop is as good as they get.
"Well boy, you ain't gonna git nothin' layin' in that bed." ~My ol' man