[quote name='Roufuss']Yea, if you can do it, then cancel Madden and keep Tomb Raider for $19.99, I'd be in for one no doubt. I'm not really sure how it would work, to be honest, since I've never placed a preorder online.[/QUOTE]
My receipt from the instore pickup shows the following:
Tomb Raider: Legend $19.99
Tax $1.70
Total $21.69
I've never done a Best Buy online preorder before, but from the website, it sounds like you don't get billed until the game is in stock. If an online order for instore pickup isn't picked up within 8 days, they automatically cancel your order and refund your money. So it sounds like you can wait for them to automatically refund your money 8 days after they get it in stock, cancel it via the web or phone, or pick it up and immediately return it. (I couldn't find any way to cancel the preorder in-store before the release date.)
Like so many other Best Buy deals, it's a package promotion. When returning just parts of the package, you run the risk of being forced to repay part of the discount (eg. they could have charged $29.99 for Tomb Raider and taken $10 off Madden.) But in this case, it looks like they are charging full price for Madden and taking the full $10 off the other game, so it really is just $10 off any $29.99 and up game.
Again - I've never done it before, so it's possible there may be a snag. YMMV and all that jazz.