This double register reward is probably a "whoopsie" on the part of Walgreens and could be discontinued/corrected at any time. So, if you don't get both register rewards, don't throw a fit and call corporate. If the deal doesn't work for you and you don't need the products, the best thing for you to do is make a return right then and there. You'll get your money back but not your coupons, so be prepared to lose the coupons! Even if you only receive one of the $3 register rewards, just over two bucks for Detergent and Dish Liquid is a heck of a bargain! This is a promotion sponsored by CouponNetwork, in case you're wondering.
