Farmer's Markets!!! SO much cheaper than the grocery store, plus the produce is local and, very often, organic. Most importantly, it's in season, so it tastes fantastic! You can freeze the veggies for later, or use them in soups and then freeze if they don't do well being frozen on their own. You can also get great deals on fruit that you pick yourself--plus it can be a fun activity to do with your family.
You can get some great deals on veggies at Sam's Club, though the whole "local" issue is at risk there.
If you cook dried beans, you can package them in containers after they are cooked and freeze them--it's much, much cheaper than cans and healthier, too!
If you get grains in bulk, try getting wheat berries and other slow-cooking grains, then cook them when you have time and toss 'em in the freezer for later. They are SO filling and good for you, but are often pretty cheap!
One great way to save money is to make things yourself. Making a homemade pizza crust is always going to be much cheaper than buying one. There was a great article on this in Cooking Light.
You can find the online version here.
One thing they noted in the article is that
eating more meatless meals is a great way to save money. We've implemented that and are now eating 1-2 meatless meals a week, and it's saved us, on average, about $20/week.
It's amazing!
Another way to save money in regards to meat is buying during sales (we have a store near us that often has great meat sales), and buying items that require work, like whole chickens. I can get a whole organic chicken at our grocery store for nearly nothing. Most of my whole chicken recipes are easy "fix and forget it" ones, like roasting or leaving it in the crock pot for the day. Then I boil the carcass to make broth and/or soup, which makes another meal. It's a major money saver, though it can take a lot of time.
Hope that helps.