Dell Discount Codes

[michboro]

I was wondering if there was any trick to using Dell coupon codes. When I try to add a coupon code from a website such as techbargains, or dealcatcher, it doesn't apply any additional discount other than the Evalue Dell code that is already applied on the Dell website. Is it that 2 discounts cannot be combined, and if so, then is there a way to remove the Evalue discount from Dell, and use another discount if it would result in a lower price??