I used to order for a store in the Midwest. While we were not as big as target or Walmart, we had stores in 9 states so we had some buying power.

At the store level, I'd get vendors coming to talk to me with certain deals too. Price per unit would come down the more we bought.

For instance, string cheese may be 2/each cost to store if I bought 10 cases, but 1.50 if I bought 20 cases.

I regularly looked at how many cases I could sell in like 2 months and order that many so we could bank the extra cash for the store.

Stores work on earning the next penny so those .50 cents would add up