I may be wrong but I don't think Gateway really does the coupon route like Dell does. What you can do is call Gateway and bargain with them... they'll usually give you a competitive priced computer to what dell is offering though Dell still comes out cheaper when you take into account the $750 coupons etc.
^^^^^ yeah, just call them or use their online sales chat. most people tend to be able to get between 10-15% off the cost of gateway purchases. the dell's will still tend to be a little cheaper, but that's because they are just that: cheaper. with gateway you'll get a slightly more "refined" product.