If you have the room for storage, you should be buying basic ingredients in bulk from restaurant supply stores

Costco is great, and we love how much organic stuff they carry nowadays, but memberships cost money, and you have to shop there often enough to make it worth the up-front cost.

Restaurant supply stores on the other hand, like Cash & Carry and other wholesalers, require no membership and carry everything a restaurant might need, so it's pretty likely they'll have what you're after.

Just like Costco, not everything is a great deal, general rule of thumb is if it's not in bulk, it's probably not a good price. However, for the things you go through a lot of, buying wholesale will save you tons of money.

Here's what we our household buys from Cash & Carry: - Ketchup. Multiple ketchup monsters in our house so we buy it in big ole cans that cost about $3, and we refill glass salad dressing bottles that we've saved, one can fills 7-8 bottles. (Keep these in the fridge) - Tofu. We make a lot of stir fry and miso soup, and buy it in big blocks for about half the price of a regular grocery store. - Soy sauce, rice vinegar, red wine vinegar, sesame oil, vegetable oil. These all come in big gallon jugs, we keep the jugs in the pantry and refill smaller containers that we keep in the cupboard - Rice, beans, lentils, flour, sugar. These all come in big sacks, we store them in the pantry in 5 gallon buckets with screw-top lids. - Garlic. Comes in a big bag full of whole heads of garlic, for less than $5, and we transfer it to a half-gallon glass jar in the fridge. Lasts forever, I cringe when I see garlic at Safeway for $1 per head. - Basil. I like to make huge batches of pesto, then freeze it in jars. When I do, I'll buy a great big bag of fresh basil (at least 10x the amount you get in those little plastic clamshells at the grocery store) for less than $5. - Hot sauce. We like things spicy, so I buy tapatio/valentina, sriracha, and sambal in big ole bottles. They cost about the same as the small bottles you would normally get elsewhere for twice the volume. We don't bother, but you could also refill smaller bottles if the big ones are too awkward.

I also make sure to browse the produce, sometimes they have awesome ripe pineapples or avocados on sale, always worth a look.

Google wholesale restaurant supply stores near you and check out your closest one, we cook most of our food and shopping wholesale saves us hundreds of dollars each year.