Ok, not a computer per se, but still a nice little deal.
I usually don't find much at the local thrift shops as around here they seem to focus on clothes & plateware. I was looking for a decent chair and for a laugh walked thru their very short electronics aisle.
Imagine my surprise when I found a very clean Epson RX-80 printer. It looked a bit dodgy in that they used packing tape to still the pieces into one pile, but I figured it was worth the $1.99 they asked. Also blew another $1.99 on a centronics cable in case I didn't have one.
Took it home, found the small ream of pinfeed I still (!) had and it worked perfectly. Held down the LF key when I turned it on, and the diagnostic worked fine. Ditto for a test page in WinXP. The ribbon is shot, no surprise there, but as I said it's surprisingly clean. No dirt, broken bits, chipped corners, yellowed plastic, etc...
Nice little piece of history there.