It's become a hobby to find the best deals that I can.
I'm not a typical grocery shopper since I work in a grocery store. I cruise the meat case every morning for markdowns (going out of date the next day). Even if I don't need it that day, and it's something we like, I'll buy it, bring it home and vacuum seal it, and freeze it. We often get first crack at overstocks since we are in the store. I haven't paid full price for meat in quite some time. When I do pay full price it's in the club store which is usually priced much better than the grocery store. I stock up whenever the price hits what I consider a good deal.
I also go to Aldi for certain things, some of their prices can't be beat. Things like cheese, cream cheese, butter, oatmeal, canned tomatoes, frozen vegetables etc... are priced great every day. I never need to pay more than $1 for a 28 oz. can of tomatoes between Aldi and the club store.
I can avoid the "Shrink Ray" as some call it, by limiting the prepared foods that I buy. I guess if you have the time, and have prices in your head or written down, shopping multiple stores can save you a lot of money. I can look at anything that I regularly buy and know in an instant if it's a good deal, or a better deal somewhere else.