Final answer:
The term an economist would use when a shopper gets a 'good deal' is consumer surplus, which is the difference between what consumers are willing to pay and the market price.
Step-by-step explanation:
The term an economist would use to describe what happens when a shopper gets a "good deal" on a product is consumer surplus. Consumer surplus occurs when the price that consumers pay for a product is less than the price they're willing to pay.
It represents the difference between the maximum price a consumer is willing to pay for a product and the actual market price they pay.
In competitive markets, the presence of many sellers and buyers, as well as the concept of pure competition, helps to ensure prices remain close to an equilibrium price, which is where consumer surplus is maximized because consumers are getting products for the lowest possible price while sellers are still able to make a profit.