Big box stores have 90 days or more to pay for their invoices. Due to their large volume orders, they set the rules to the distributors.
In the case of small businesses, they must pay in advance for their orders (in some cases it’s over 6mos in advance). They don’t get a volume discount.
I’ve run small businesses. Here’s an example for you:
I buy 20 cases of baseball cards direct from a company. I pay $400 per case 6 mos in advance.
A big box store orders 1 case for each store. They pay their invoice 90 days after delivery.
They also get a small percentage discount for the volume of their order.
We both receive our orders at the same time. I sell mine for a 20% profit. The big box store sells theirs for a 10% profit on the non-discount invoice price (they may have already gotten 5 to 8% or more of a discount off their initial order price).
The big box store sells out of their product within the first week. They put the money in the bank and get compounded interest on their money for the entire 90 days prior to the invoice due date.