Having come from a long line of law enforcement professionals, I would recommend that you follow the rule of occupation that has served my family well.
Rule: Do not police your neighbor's, family or friend's. Let the other cops do that. You police THEIR neighbors, family and friends. It all works out better that way.
Regardless of your disdain, you will never find a way to be the "good guy" in this. Report them if you must but be prepared for blow back. For I assure you, in the end you will be made out to be the bad guy. It's kind of like telling someone their significant other is cheating on them. You can never win.
But if you wanted to tell the powers that be that the store is trading beer and cigs for food stamps, I suppose that might give you some solace. But do that knowing that there are 10,000 similar reports like that ahead of yours.