You lucky motherforgeter.
Charity shops (and sometimes but not as often, pound shops) are magic for old things.
Other things i've gotten: Sega master system; £13, Monkey island 2 (Commmodore floppys) £5 (i don't even have a atari but i wouldn't pass it up.)
I also got a Game Boy Camera from a idiot at school, He traded it for pennys worth of food.