Hubby and I also save tons and tons of money through stockpiling. A small chest freezer was our BEST money-saving purchase. We also have HUGE pantry in our kitchen.
You do have to select your stockpiled foods carefully though. We only stock up on foods that are incredible bargains. No matter how good the bargain, we avoid junk and our personal trigger/binge foods.
We start our shopping most months at a local overstock store (sort of like a privately-owned version of Big Lots). If the price is awesome, we stock up. A couple years ago they got in a huge health food store shipment and we bought a lot of pantry items. They had pound bags of gourmet varieties of dried beans ($3 to $4 for a pound bag in the health food store) for I believe 29 cents per bag. I bought one of every variety (chick peas, black beans, pinto beans, red beans, anasazi beans, kidney beans, white kidney beans...) and (in hindsight) I wish I had bought 5 bags of each variety (but I didn't know whether hubby would eat the more exotic varieties of beans).
I learned that most beans are completely interchangeable in recipes. I would make a batch of beans in the crock pot (the whole pound bag) then I would drain them and freeze them in a ziploc bag and "moosh" the bag around every 20 minutes or, to separate the beans as they froze so that I could scoop out just what I needed for recipes.
I buy spices in bulk from health food stores (where I scoop my own) or from a local baking supply spice store that sells the spices in small plastic tubs and plastic bags rather than in glass or plastic spice jars (cheaper, fresher, and much better tasting than grocery store spices in glass or plastic jars).
I make my own salad dressings (I've read and been inspired by tons of recipes online, but I learned the splash-and-dash method from my mom and grandma so I rarely make a whole batch. I try not to have any leftovers).
Kwik Trip is a gas-station convenience store with great prices on butter, eggs, milk, orange juice, potatoes, onions, bananas, apples, oranges, and pears. The prices are so much cheaper than the regular grocery stores. I just bought a bag of apples that had to weigh at least 5 lbs, for only $3.99 and choice of Ambrosia and Fuji (both premium varieties of apples).
I always refrigerate apples, because they last 10 times longer in the fridge (and I LOVE the crisper, juicier texture of refrigerated apples).
We don't buy fresh potatoes in bulk though. We both watch carbs, so we don't eat them fast enough. We do buy potato flakes though (I add a little bit of mashed potato flakes to my mashed cauliflower. Almost as low-cal as mashed cauliflower alone, but with a taste and texture more like real potato-only mashed potatoes).
We buy granulated tvp and brown it with ground beef (or pork) and seasonings (onion, celery, bell pepper, garlic, parsley) and freeze it like the beans (mooshing the bag so it freezes in crumbles to use in recipes). By combining the tvp and ground beef I can use cheaper (fattier) cuts ground beef and yet replicate the fat content of premium super-lean beef (because tvp is virtually fat-free). The crumbles can be used in any recipe that calls for browned ground meats, like tacos, sloppy joes, casseroles, spahetti sauce, chili, stroganoff....
I bought some "ground beef" recipe cookbooks at thrift stores and on amazon.com too.