Yakuzaice on 23 April 2011
Amazon tends to have games around 10% off at some point before they are released. Plus they often have $10-20 credits to go along with it. For example I just got Portal 2 for around $55 and I received a $20 credit.
I don't really get your final point though. I can't really see an individual game being better off when everyone is giving a preorder discount than if it was only that one game. I just can't see millions of extra people preordering for $5-6 off. Especially when they could probably wait a week and get a better deal than that.
