You want a really good frugal tip? Stay home. Don't go shopping until/unless you really need to, and continually revamp what "really need to" means. It's best to plan on one day a week, or every other week and refuse to shop before then.
When I was growing up, we lived on a ranch 20 miles from town. Mom didn't drive and Daddy worked 7 days a week. We went to town once a month, when Daddy got paid. Toward the end of the month, we ate just as well as we did at the beginning (you thought I was going to say we ran out of everything!). The exception was that when we got home from our trip to town, we had sandwiches on "boughten" bread, with lunch meat.
It's true that we sometimes ran out of things, but we made do, or did without and it didn't make that much difference in how we lived.
Did you know that it isn't critical to have cheese on hand? And that you can wash dishes with laundry detergent if you need to? And... that you can make a meal from a handful of rice, a chicken leg and a bag of wild greens? Or whatever you have on hand.
Making do is just as much a frugal and sensible pursuit now as it was back then. The truth is that we're spoiled into thinking that we have to run to the store when we're out of two or maybe three items. If we're out of more than that, it's panic time.
But if we would calm down and admit that doing without commercial bread for three days won't send us to our graves (it may help keep us out of them), we wouldn't have to run to town every other day. It's true that the more often we're inside a store, the more we spend there. Staying home makes frugal common sense.