depends what you have and who will do it.
I've gone two routes, ReMan for $800 ($1200 installed) and a rebuild for $650. . . unless there is something major wrong, cracked case, messed up planetary etc. Rebuild would get my vote. Both were done by Trans and Gear shops. Third option if you can swing it is JY, those vary in price but i'd expect like $250 or so. . .
Labor to put in ????