Well, gamefly has a 20% off coupon. Assuming you're in the states, that comes to $56 for the deluxe edition. The standard edition is $48 with the discount. (Which is cheaper than amazon's price of $49.79)
I'm not sure about Europe. There are a bunch of sites which seem to be selling a deluxe cd key for pretty low, if you trust them. That's only for Europe though.
The gamefly coupon, which is valid through sometime past August 20, IIRC, is
EDIT: There's a UK version of this coupon too. I believe it's
PSN: CrossFire311 "You beat death, Arvin. But you couldn't beat me."