Damn, all this talk about Commodores and Amigas makes me want one. My best friend had a C64 and a big bookcase full of boxed games. Pretty impressive collection, I think I remember playing Rambo III that Cosmic posted above. Although the game I remember playing most is Pirates!.
So there's a Commodore Plus/4 w/box on CL for $30. Although I read that it's incompatible with C64 software. So I probably wouldn't go for that other than for collection purposes. Also saw an Amiga 2000, but I don't know how much the person wants for it.