That is… Not quite the same as I thought whenever I read that word. Around here, a co-op is a collective purchasing program or a store that participates in a similar program. They buy foods in bulk at wholesale prices. By bulk, I don’t mean the family size bags available at a membership club like Costco. I mean like a 100lb bag of flour meant for a restaurant or an entire pallet of something.
A group of people get together and make note of what they want to buy, and if enough people want the same item it gets purchased. Then they all meet up on delivery day and split the item at the amounts they paid for.
I’m assuming that is very different than what you are describing.