Final answer:
The term for a reduction in cost for prompt payment of inventory is a discount, and it's comparable to a shopper getting a good deal on a product, which means purchasing at less than the market value.
Step-by-step explanation:
The term used for a reduction in the cost of inventory purchased that is given for paying promptly is a discount. This incentive is often provided by suppliers to encourage quick payment and improve cash flow. In essence, this is similar to what economists would describe as a shopper getting a "good deal" on a product, which typically means the shopper is able to purchase something at a price less than what is considered the market value, thus receiving more value for their money.