Definitions of bargain:

• noun:   an agreement between parties (usually arrived at after discussion) fixing obligations of each

  Example: "He made a bargain with the devil"

• noun:   an advantageous purchase

  Example: "She got a bargain at the auction"

• verb:   come to terms; arrive at an agreement
• verb:   negotiate the terms of an exchange

  Example: "We bargained for a beautiful rug in the bazaar"