I recently got a HT from Dr. Alexander and paid $4 per graft (2500 - $10,000). I am not sure if he "barters" as I did not try, but I would bet that some hair surgeons would drop their price if you talked to them.
On a side note -- I went on a consultation with Dr. Williams in Las Vegas, NV nearly 3 or 4 years ago and did not use his services; however, nearly 2 years later, a representative from his office called me and offered me a "deal" if I was willing to do a HT surgery with him. Thus, I think some surgeons are willing to work with you.