Best deals for me have to be being given an original A500 (1.3) a couple of years ago for free and finding an A600 with mouse and PSU at a car boot sale for £3 about 4 years ago.
Both work perfectly, although I had to find another A520 for the 500 as the one that came with it had no sound coming out of it for some reason........ luckily one turned up at a car boot for £1 not long after getting it!
Used to have an original A500, which got sold when the A1200 (which I still have boxed, but lurking in the loft) came out. Still wish I had my original A500 for some reason.... pure nostalgia I guess.
Funny, I've now got 3 Amigas and never use any of 'em due to lack of space. WinUAE does a grand job, but I'd hate to get rid of the original hardware.