Some people think old car parts are worth their weight in gold, but many folks just want 'junk' gone. Sometimes you really gotta dig to find the deals. I found my 833 in Vegas after talking with a few folks at a driveline shop - they hooked me up with a guy who had just finished his swinger and then got t-boned by a kid on their phone, and he was parting out the car cheap after he got a decent insurance settlement from it.
I've seen 2-3 OD a body 833's here in N. Idaho, and at least 2 non OD A body 833's. One was asking $1800 just for the box, and at the other end was a guy swapping an auto into a car for his daughter and had the whole shebang (from pedals to yoke) for $750. So it just depends. I should have grabbed the cheap one, but I wanted new shocks and other parts for my car more than I needed a spare trans.