Toys R Us has a sweet deal annually around this time. You buy 2 games and get the 3rd free.
This excludes Pre-orders but you can use a placeholder for some.
Placeholder Example.
You buy 2 games you want and 1 that is a placeholder to get the game released AFTER the sale.
For this example we'll use Fable 3.
So you'll purchase 2 full price games, MW2, Dead Rising 2 and 3rd free game.
If you're going the placeholder route you MUST make sure the placeholder game is rung up 1st or 2nd.
Or else you won't be able to exchange it because the receipt will show $0.00 for the 3rd game.