Believe it or not, we shop at ALDI. If you've never been to ALDI, it's quite an experience. The stores are never out front on a busy street. You usually find them tucked off behind some of the more prime real estate. They don't accept credit cards to cut costs; it's cash only, though they do let you make a PIN purchase with your ATM/Debit card. In order to take a cart, you have to put a quarter into a release mechanism. If you return your cart instead of leaving it in the parking lot, you get a quarter back. There are four or five total aisles in the store, but you can walk out with almost all the essentials. You bag your own groceries. And, if you fill your cart as high as you can get it without stuff falling out, you might possibly just barely break the $100 barrier.
You can't get everything there. In fact, if you shop for groceries there you typically have to make another trip to a different store to get some of life's little extras, or things you're unwilling to settle for off brands of like pop or t.p. of reasonable quality. But usually you'll find some name brand stuff. It depends on what they can get deals on, but you can typically get fresh produce and pringles and baking mixes and that sort of thing. And all of it is less than the jacked up prices you pay at Kroger and Giant Eagle, even with their slightly-reduced-gouging-at-the-expense-of-tracking-your-every-purchase loyalty cards. The extra trip you have to make to those stores to fill the rest of your grocery list will fill only 1/2 our cart, but cost much more than the ALDI trip.
They don't advertise so that they can save money, but Unwrapped on the Food Network did a little blurb on them in one of their shows. You really can't go into ALDI with a list and expect to get everything you need, but if you're willing to forfeit a bit of pride and convenience, you save a ton! Your mileage may vary, but I track our family finances very closely and we spend 1/3 less a month on groceries for our family of 4 during months where we make it to ALDI. We save about $2000 a year by shopping here.
In addition to cutting me and the boys hair, being willing to drive older and used cars to bypass having car payments, working at our church's preschool so that the kids get free tuition, and finding us the greatest deal on a cell phone plan of anyone I know - my lovely wife sacrifices to make an extra grocery trip so that we can save. It's stuff we probably wouldn't do if we both worked full time, but it has a visible and significant impact on the way our house runs. I think that a lot of people forget that there are two sides to the family finance equation - income and expense. Income is the harder variable to tweak, but by controlling expenses our income goes much further.