I bought my '91 318i sedan on CL. High miles (266K), clean body, not running, bad diff. I had enough change left over from $1000 to fill the tank after I got it running. Not a bad deal, all-in-all.
Among other CL things, I've found:
A non-running '87 325is with a good title...and five 14" basketweaves, black leather sport interior, premium sound, etc....$285 including the title transfer. I'm still sitting in that black leather sport seat!
A "rusty but trusty" running '84 325e auto with five good bottlecaps, nearly new tires and a tan leather sport interior including the rare rear headrest option. It was a tremendous bargain for $200 (a lot of people called but I was the only one that showed up). It was too far gone to save, so I stripped it & sold it for $250 to a scrapper for "farm use." I'm almost done with the last of those tires on my 318i.
Most of the deals I made have only been break-even, but with those three I'm way ahead!