What is the term for whatever the promisor demands and receives as the price for his promise?

The term that refers to whatever the promisor demands and receives as the price for his promise is "consideration." In the context of contract law, consideration is a fundamental element that involves something of value that is exchanged between parties.

For a promise to be legally binding and enforceable, there must be consideration; it acts as the incentive for the parties to enter into a contract. Consideration can take various forms, such as money, services, goods, or even a promise to refrain from doing something. The essence of consideration is that it must be something that has value in the eyes of the law, which motivates the parties to fulfill their respective obligations.

In contrast, compensation, payment, and benefit do not specifically capture the legal definition of consideration in the way that this term does. Compensation typically refers to payment for losses or damages, payment is a transaction of money for services or goods, and benefit may refer to an advantage or gain that a party receives as a result of the contract but does not encompass the idea of mutual exchange that consideration entails.