If you shop at CVS then you have to understand ECB's. That is Extra Care Bucks. They are CVS money you earn when you shop that can be used to purchase more items (regular price, sale, or clearance.) Using sale/clearance items, coupons, and ECB's is what makes CVS a fun adventure.
My first trip was forced as it was to fill a prescription. I knew I wanted the coke deal so picked up my Q's and headed out. For filling my prescription I got 1.50 in ECB. I then took that and paid $13.50 ($15-1.50) and got 5 - 12 packs of diet coke ($2.70 per pack.) That is a good price, but I also got $5 back in ECB. With that I got 2 bags of cough drops, 2 kitchen sponges, and a carmex for FREE! Good price on coke and $5 free stuff (all needed and usable) is a good day at CVS!