Not anymore. They just made it so that only one "gift card" and only one coupon can be used at once.
Ugh... that is lame. So if I have several gift codes, I can only use one at a time, and still have to pay the balance? What if I don't use the whole amount? Do I still have a remaining balance on that code?
Actually, they have set up a new system where you can use more than one now as long as the points used to make the codes were earned in your account!
It was only temporary that you couldn't use more than one.