A contract is a bargain that is legally binding.
Wharton.

And whon your honors mean to solemnize
The bargain of your faith.
Shak.

She was too fond of her most filthy bargain.
Shak.

Bargain and sale (Law), a species of conveyance, by which the bargainor contracts to convey the lands to the bargainee, and becomes by such contract a trustee for and seized to the use of the bargainee. The statute then completes the purchase; i. e., the bargain vests the use, and the statute vests the possession. Blackstone. -- Into the bargain, over and above what is stipulated; besides. -- To sell bargains, to make saucy (usually indelicate) repartees. [Obs.] Swift. -- To strike a bargain, to reach or ratify an agreement. "A bargain was struck." Macaulay.

Syn. -- Contract; stipulation; purchase; engagement.

So worthless peasants bargain for their wives.
Shak.

To bargain away, to dispose of in a bargain; -- usually with a sense of loss or disadvantage; as, to bargain away one's birthright. "The heir . . . had somehow bargained away the estate." G. Eliot.