Consistently, this is what I buy in bulk (other than the usual dry goods, which is probably pretty standard for all):
- Rice (brown and white, generally keeping 10-15 lbs on hand)
- Beans (5-8 lbs)
- Pasta (5-8 lbs)
- Soy and/or rice milk (they don't need to be refrigerated so they go into the garage and are great fill-ins when we run out of cow milk)
- Flour (25 lb bag; put what I need into the kitchen container, store the rest in the chest freezer in the garage)
- Olive and vegetable oil
- Herbs and spices
- Cheese (this is the only non-perishable we buy in bulk; we split the bags of shredded cheese and freeze it in halves or quarters)
I do not buy snack foods in bulk because I try to avoid family consumption of these items anyway. I don't tend to buy canned foods in bulk because of the different reports I hear about chemicals in the manufacturing process that may leech into the food over a period of time if not used -- plus I happily can my own when I have the produce to do so and most of the CostCo stuff has ingredients I don't care for (added sugar, salt, preservatives).
In general, although we have a small family of only four (and they're little ones), I bake/cook using full recipes and then freeze or jar/can the remainder so that we only use what we need and we have plenty for later. It also makes for good gifts and for "quickie" meals when we're beat after long days at work and need to just throw something into the microwave or oven.
As far as quick and cheap meals are concerned -- my faves are anything using pasta or rice.
Pasta - boil some up quickly, add a little olive oil and some of those CostCo herbs, and you have dinner!
Rice - cook as many cups as you want. Use what you must and then put into freezer storage bags the remainder (we put it into 1 or 2 cup portions). To thaw, just drop into a bowl of faucet-hot water or toss into the microwave for 30-second increments until you can get it out, then transfer to dish to warm the rest of the way. Add in beans, corn, cheese, salsa (some chicken strips!) for a delicious Mexican style bowl.
Potatoes - boil and mash. Put into freezer bags whatever is unused. To thaw, do so at room temperature or in a bowl of faucet-hot water.
Veggies - Take fresh veggies (any kind), put in a bowl with 1" or so of water and cover with a paper towel or lid. Cook in microwave for 3-5 minutes to "steam" to desired level of tenderness.