The hitch itself came with just the metal bits, ran about 250 or so, as for the hardware, I had to get four nuts for the mounting bolts (whopping $2.50 in parts...) got the wiring bits new from BMW.

part number for the wiring kit was 71 60 0 009 698. That part was about 160 IIRC

not much (if any) cheaper than brand new, but it was AVAILABLE, and that made the difference to me