Fortunately, all the Amiga gear I've ever received has been OK. I've never found any "crazy" deals either (like the A4000 for $150), but I did get an A500 stash once for free, which included an A530 Turbo, an ICD AdRam 540 (fully populated), various custom chips and software, etc.
I'd love to walk into a local thrift store and find something cool (like 10 NIB A3000s), but the chances of that happening here are pretty slim . ;-)