rebuilds gonna cost more the 700.

you can search Craigs list for part outs, sometimes they are still in the car and can be tested at least. other times you need to trust them. ( hard i know)

used tranny runs around 400, ( more or less) a install at a shop runs 4 to 500 easy with fluids and filter for the trans. unless you can swap it yourself, then you'll save the install money.