Fair price for a complete RTS is between $250-350, but you have to make sure it has all of the hardware, as a lot of it cannot be purchased separately. I have discovered as many of the part numbers as possible, a missing cross bar or a-pillar bolt is replaceable, but you cannot buy the brackets, B-pillar bolt/plates or lock socket anywhere.
EDIT: I updated my website with a breakdown of the hardware necessary for the RTS, with part numbers, it's under q&a.