I'd grab an amy from the dumpster if I saw one... The peecee I'm using now was left on the side of the road for trash pickup. It's only a PIII/550 mhz machine, but it was better than what I was using. Came with a nice Sony 17" monitor too.
Last time I saw an Amiga at a thrift shop was many years ago at the GoodWill. I bought a 1000 for 6 bucks, because I needed a floppy drive for my original 1000. When i got the thing home and found that it still worked, i couldn't bring myself to part it out.
The local gov sponsors a e-waste recycling drop-off. I've been meaning to see if they let folks paw thru the junk over there..