When you have to eat the things that are on sale that week, I think it is an inefficient use of your time and money. First, what if nothing your family likes is on sale? What do you eat? (spend more than you have to get something they will eat?) Second, what happens when a need such as a doctor visit, emergency out to eat desire etc. comes up and you could really use your grocery money for that instead of food? What do you do? (go into credit card debt and hope you can pay for it later?) Third, what happens when you desperately need toilet paper and nothing is on sale? (pay more?)
I choose to eat and live from my pantry, not from what's on sale. In my pantry and storage I have many months worth of non-perishable food and household goods. When we need toilet paper the four-year old runs down and gets some.
Everything in my home "store" is on sale because I buy everything on sale and/or with coupons. I stock up when the price is low. When I notice another great price on toilet paper and we have room (in the budget and the store room) I buy more.
We are able to eat the meals we like and are used to. I watch for good deals on the ingredients I use for our favorite meals, then I stock up.
When a small emergency comes up and we need money for doctor visits, medicine, etc. I can use my grocery money for those things and simply skip grocery shopping for the week. I will occasionally grab a few perishables like fresh fruit/veggies or milk and cheese, but we could get along without it. It is also great for those weeks when mom just doesn't feel like shopping or there aren't any really great deals I want to stock up on. Then I have extra cash to play with!
The idea of the pantry or food storage is, in my opinion, the best way to save money on your grocery bill. When you are just starting out with building your storage you won't see a huge savings because you still need to buy those necessities you haven't found great deals on yet. But, once established the amount of money you'll have to pay for groceries will drop.