In my area (northwest Boston suburbs) the Market Basket chain has the 12-oz. Corn Flakes at $2.19. My local store got me six cases by special order. They went along with "no planes, no sale" when I explained the reason. The cereal went to a local food bank. I kept the coupons. (Their volunteers and I had fun tearing up boxes.) Not quite in Pudding Guy's league, but you do what you can ...
By the way - if you ever have to fill out 90+ coupons (I eat the stuff, too) you may care that labels are OK as long as ALL the info is there. (I called Kellogg.) My computer prints them by the dozen onto Avery label paper.