[quote name='PhantomaZero']You sure its not 10% off and then another 10% off that? A lot of stores will do that. =\[/quote]
Both EB and GS, over the past several years, just stack the coupons/savings on top of one another. Granted, most retailers do the more mathematically-correct discounts when you're at the counter but, at least at EB/GS, they don't care all that much.
It used to be a bit better, too. I loved the B2G1 sales where it also took off 10% on the "Free" title as well. Those were good times. ;D