Jake is an excellent barber. however, all customers who come to him for a haircut must buy a bottle of shampoo. this type of arrangement is known as a tie-in sale. a sweetheart deal. an exclusive contract. a cross subsidy.
The answer would be a tie-in sale. Marketing arrangement in which a supplier of an in-demand good or service sells it on the basis that the buyer (usually a retailer or reseller) also buys a certain amount of another (less popular) product. Also called tie in arrangement. See also full line forcing.
