WordNet (r) 3.0 (2006):

horse trading
    n 1: the swapping of horses (accompanied by much bargaining)
         [syn: horse trade, horse trading]
    2: negotiation accompanied by mutual concessions and shrewd
       bargaining

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "horse trading":
   agency, barter, bartering, brokerage, buying and selling, dealing,
   doing business, exchange, give-and-take, interchange, jobbing,
   merchandising, retailing, swapping, trade, trading, trafficking,
   wheeling and dealing, wholesaling