How did you get this code to stack with the e3 promos? contact amazon CS?
The VGAUGUST code at Amazon does NOT stack with the E3 discount. The only way you get additional discounts on your E3 order is through price adjustments, which require the list price of the item to change. In other words:
Fallout 4 was $79.99 during E3. The page now shows $71.99. This game will get its price adjusted on all pre-orders, meaning instead of the original 30% off $79.99, you'll now get 30% off $71.99 instead. Generally, if the sale price of the individual item is lower than the sale price listed in your E3 order, you can expect your order to adjust automatically to match the new lower price, and then get 30% on top of that.
DanganRonpa Another Episode was $49.99 during E3 and is still $49.99 now. While it is eligible for the VGAUGUST coupon as well, the base price has not changed. Coupon codes do not affect the sale price on individual items, and thus will not trigger a price adjustment.