If you have 3 $50 games, the $15 off coupon will make one of those $50 games cheaper than the rest and you'll end up getting it for free anyways/coupon wasted.
I'm sure this question gets asked all the time. So forgive me for being redundant if so. If you have a power up rewards by two get one and also a $15 off used the coupon, can they be used at the same time?
If you have 3 games that range in price, then you should be good...maybe a $50 game and a couple of $40 ones