The article above is pretty good, but Business Insider's ads are awful - the site won't let you use an ad blocker, and the ads take forever to load. Some of their "skip" things are aimed more at single people or small apartments.
We buy paper towels, tissues, and toilet paper when they go on sale at Costco, and keep loads of them in garage - but you can't do that in a smaller living space. Same with things like big jugs of Cascade, which we'll have like 4 of under the sink.
If you can buy when the bulk items go on sale or have coupons and store them somewhere, it's great - but you have to think ahead and buy during sales to have an extra on hand, rather than waiting for need.
We also buy their three huge bottles of ketchup, because we go through it quickly (we also use it as an ingredient in some recipes, which helps).
Cereal is a big one. Bananas. Eggs. Bread (if you eat enough of it, because you need to buy two loaves at a time). Bacon (comes in two compartments, we'll sometimes use one and freeze the other).
It really helps if you have extra freezer/fridge space, too.
