Final answer:
An economist would describe a shopper getting a 'good deal' as obtaining a high degree of consumer surplus, which indicates they've achieved extra value compared to what they were willing to pay.
Step-by-step explanation:
When a shopper gets a "good deal" on a product, an economist might refer to this as the shopper achieving a high degree of consumer surplus. Consumer surplus occurs when the price that a consumer is willing to pay for a good or service is greater than the actual price they pay. The difference in these two amounts represents the consumer surplus, where the consumer feels they've gained extra value in the transaction.