It doesn't matter if you're looking for new styles or already on-sale items. The discount will apply to anything you can find.
Each sale has it's own promo code, which I posted below. Also, if you spend $50 or more at either of the brands and shipping is included free of charge.
Click here to go to Gap and use code GAPHAPPY for the discount.
Click here to go to Banana Republic and use code BRAPRIL30 for the discount.