If you use anywhere close to 3 cans of tomato sauce in a single recipe, buy the 108oz cans of tomato sauce and just double your recipe. Here I can buy one can for $2.72 and use it instead of 7-15 oz cans.
So this morning I put 1-108 oz can of tomato sauce, two pounds of cooked hamburger, some chopped onion, garlic, and 1-1/2 Tbsp of basil in the crockpot. I then made some French bread and dinner is about to be served.
PS. It works great to buy peaches and pears in the large cans too. They last in the fridge long enough for a family to eat them up.