I was in my local WHSmith Store today (Plymouth) and noticed a box of sale items of games without cases. I got Lego Star Wars for £3, there were other copies of this game there. there were also other PS2 games, PC games, Xbox games, GBA games, all for no more than £6 and from £1!! All games had no box, game disc was in a sleeve with instruction booklet attached.
There was also a game called conflict: Vietnam for £3, I can't remember any of the others, oh and also some UMD movies I think.
If you're not bothered about the box this is an absolute steal!! (obviously you have to actually pay for it ;-) )