t is to convenient for most people to go to the store to get it and let the store keep it in stock rather than to have extras of anything around the house.
I've figured out there's very little you need to pay full price for if you plan a bit.
I have about two dozen cans of Tuna in the cupboards right now. But I noticed the brand and style I like is on sale for $1/can v. $1.67 for what I usually buy...so I'll grab another dozen tomorrow when I'm out on other errands (the shelf was empty and I didn't want to wait to re-stock or get a raincheck today).
I almost never buy yogurt now, unless one of the brands I like is on sale. It was Buy 1, Get 2 free today for one I like today, I'll be eating a lot for the next several weeks
But it's not a necessity...it's a nice treat when on sale.
Most times I don't leave the Supermarket with less then a 40% savings off the regular prices -- and I have two things working against me. I don't have a big freezer to store stuff in, and I'm only myself here so I can take full advantage of some of the sales -- too much for one person. Bag of apples were buy 1, get 1 today but I didn't think I could eat two bags soon enough.
I try to stop once a week at the supermarket to pick up fresh(?) produce and just see what's on sale.
Of course, right now at my house...as long as I pay the light bill and the internet bill I could be fed, warmed, and entertained without leaving my house for two months if I had to. Maybe three.