Loss leader

Etymology

An American retail coinage from the early 20th century, combining “loss” with “leader” in the sense of a featured item that “leads” customers in. The tactic is old enough that several U.S. states passed laws against selling below cost.

noun phrase · /laws LEE-der/
A product sold at a loss or very thin margin to lure customers who will then buy other, profitable items.
What it names
The deliberate bait — the cheap staple at the door — that a seller accepts losing money on to capture the larger sale.
Example
Grocers price milk and eggs as loss leaders, betting you’ll fill the rest of the cart at full margin.
Related idea
A loss leader sacrifices margin on one item to profit on the basket; drip pricing instead hides fees until checkout, and a Veblen good runs the opposite way, selling more because the price is high.