With Halo Reach set to release September 14th, you can preorder your copy at Amazon and get $20 in Amazon Credit toward a future game purchase.

Pre-order Halo Reach and get $20 off a future video game purchase. The promotional code will be placed directly into your Amazon.com account within 2 business days after the product ships. Offer valid when shipped and sold by Amazon.com. Promotion valid on all existing orders. Limit one per household. Amazon reserves the right to change or terminate this promotion at any time.