Hmm so your sales tax is 8%. My state is 6%. So assuming Cashback doesn't factor in tax it should still be $100 off.

530 ($500 + 6% MD TAX = $530) - 100 = 430 - 50 rebate = 380.

Way better than my Amazon which is

$529 - my $50 in gift credit - 50 rebate = $429. About a $50 savings. But the issue is if I switch to Dell when on Earth am I going get the n900. Already it looks like I won't be getting the n900 into well into December.. Not to mention Dell puts the charge date on the invoice which means if I get it in Jan. I won't be eligible for the rebate (it's only for purchases between Nov. 16th and Dec 31st). While with Amazon they put down the pre-order date.

Hmm..

Edit: Wait I did it wrong..Dell has the n900 for $600.

So 20% cashback would only be $120 off. 600-120- $50 rebate = 430. So no real savings at all.