500-600. can vary a little more depending on whether you buy 'privately' or from an importer etc
also need:
-bellhousing
-clutch spline changed from T50-W58 (should cost less than 100)
-gearbox mount (stock, most gearboxes will come with one)
-gearbox crossmember (custom)
-shorten tailshaft and change front yoke, or get a whole new tailshaft made up (200-500). apparently you can just use the front-half of a certain car's tailshaft and match it up with the rear half of an ae86 shaft, but i don't know which one
-speedo drive stuff