I paid around 1100 for a fully rebuilt m5r2 from a reputable shop.
New Parts:
brass synchros
new clutch, T/O bearing
slave cyl
You could save yourself a bit of money by removing the transmission yourself. I had mine rebuilt when I was still timid about working on SC's, but it really isnt that hard. I recently took part in pulling the tranny out of an early model sc. Almost makes me mad I paid someone to do mine.
Adam