The Collaborative International Dictionary of English v.0.48:

Bargainee \Bar`gain*ee"\, n. [OF. bargaign['e], p. p. See
   Bargain, v. i.] (Law)
   The party to a contract who receives, or agrees to receive,
   the property sold. --Blackstone.
   [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

BARGAINEE. A person to whom a bargain is made; one who receives the
advantages of a bargain.