In the last month I've gotten a working Performa 575 by posting a "Wanted" on our local Freecycle. It's missing the back I/O plate, but it works great.

I also picked up a Quadra 605 with a cracked case, a 660AV with a broken locking tab and a Powermac 4400 off of the computer ads in Craigslist. The seller wanted $15 for the power mac and was just getting rid of the other two. I asked about the Quadra and he gave me all three.

Now if only I can find an SE/30...