Source : Webster's Revised Unabridged Dictionary (1913)

Bargain \Bar"gain\, n. [OE. bargayn, bargany, OF. bargaigne,
   bargagne, prob. from a supposed LL. barcaneum, fr. barca a
   boat which carries merchandise to the shore; hence, to
   traffic to and fro, to carry on commerce in general. See
   {Bark} a vessel. ]
   1. An agreement between parties concerning the sale of
      property; or a contract by which one party binds himself
      to transfer the right to some property for a
      consideration, and the other party binds himself to
      receive the property and pay the consideration.

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

   2. An agreement or stipulation; mutual pledge.

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

   3. A purchase; also ( when not qualified), a gainful
      transaction; an advantageous purchase; as, to buy a thing
      at a bargain.

   4. The thing stipulated or purchased; also, anything bought
      cheap.

            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.

Source : WordNet®

into the bargain
     adv : in addition; over and above what is expected; "He lost his
           wife in the bargain" [syn: {in the bargain}]