Not sure how long this deal will last (as in until what time), but if a local store has a good deal on 12 packs today, you can basically buy 3 and get 1 free.
Each 12 pack has a code for 10 points. 3 codes will get you a coupon for a free one.
So for example, if your local store has them for 4/$10 and you buy 12 packs, you will have spent $30.00
Then you enter in the 12 codes and get 120 points (maximum you can enter per week)
You redeem the 120 points for 4 coupons. You will have spent $30 on 16 packs making each one $1.88