To get an additional 2% off from Dell Home, begin the checkout process.
During checkout, choose to pay with one credit card online, as shown here:
Then, when prompted to get 2% off by paying with a Dell Preferred Account, choose it as shown here:
If you have a Dell Preferred Account, use your account to get 2% off of your purchase.
If you don't have a Dell Preferred Account, you can apply for one and get instant approval if you have decent credit.
I personally do not like to have too many credit cards, but the Dell Preferred Account is very useful to have, because of discounts like this, and other future discounts which you will be able to take advantage of.