a mutual voluntary agreement between two parties for the exchange/purchase of some specified goods. The term also implies negotiation over the terms of an agreement.
EXAMPLE:
as a favor to his neighbor, John agrees not to erect a swing set in his backyard. Two years later, John’s grandson moves in with him. So, John [reluctantly] decides to build a swing set – to keep his grandson happy. He is not prevented from building the set even though he had previously told his neighbor he would not erect one. The earlier agreement is not binding on John because it was not a bargained-for exchange. The neighbor provided nothing in the agreement [as consideration] for John’s promise. Thus; the promise was a gratuitous one.
