This sounds crazy - but the cheapest place I have found for games in in my Blockbusters underneath my apartment! They have some sort of gaming place inside them which sells full price games, and then pre-owned ones. These pre-owned ones are about £19.99 for a brand new game, and they dont even look as if they have been used! I've saved myself a small fortune buying from there!
Managed to pick up 6 golden oldies (Tomb raider 1,2,3 and a few other games) for less than £20! All of which I was after
I went and had a look in there "Bargin Basket" thing today! Disgracful, a second hand copy of Halo for PC at £25.
Its cheaper brand new at www.play.com . Its the online online shop i really use, i've spent around £600 there and i've never had 1 problem with anything they've sent me. The longest i've had to wait for a delivery was about 7 working days, which still isnt that bad.