Walgreens "Secret" Register Reward

I stumbled on this one by accident and I read on another blog about someone else doing the same.

Buy 3- 3 Musketeer Crisps $.69 each

 get back $1 RR

Buy 4- get back  $1.50 RR

They are $0.69/1 or 3/$2 before RR.

= 3/$1 ($0.33 each) or 4/$1.19 ($0.30 each)