Amazon is running a $20 promotional credit for pre-ordering the Xbox 360 exclusive that can be used to buy other Amazon products online. Meanwhile, Walmart.com is offering up a $20 eGift Card for those that pre-order Gears of War 3 that is good for online purchases as well..
Amazon offers free shipping but local sales tax is applicable in select states. Walmarts free Ship-to-Store delivery method is not available but you can still get 97 cent delivery. Local sales tax is still applicable of course.