The Collaborative International Dictionary of English v.0.48:

Dicker \Dick"er\, n. [Also daker, dakir; akin to Icel. dekr,
   Dan. deger, G. decher; all prob. from LL. dacra, dacrum, the
   number ten, akin to L. decuria a division consisting of ten,
   fr. decem ten. See Ten.]
   1. The number or quantity of ten, particularly ten hides or
      skins; a dakir; as, a dicker of gloves. [Obs.]
      [1913 Webster]

            A dicker of cowhides.                 --Heywood.
      [1913 Webster]

   2. A chaffering, barter, or exchange, of small wares; as, to
      make a dicker. [U.S.]
      [1913 Webster]

            For peddling dicker, not for honest sales.
                                                  --Whittier.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dicker \Dick"er\, v. i. & t.
   To negotiate a dicker; to barter. [U.S.] "Ready to dicker.
   and to swap." --Cooper. Dickey

WordNet (r) 3.0 (2006):

dicker
    v 1: negotiate the terms of an exchange; "We bargained for a
         beautiful rug in the bazaar" [syn: dicker, bargain]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "dicker":
   bargain, barter, beat down, bid, bid for, chaffer, cheapen, deal,
   drive a bargain, haggle, higgle, huckster, jew down, negotiate,
   negotiation, outbid, palter, trade, underbid