WordNet (r) 3.0 (2006):

sales force
    n 1: the division of a business that is responsible for selling
         products or services [syn: sales department, sales
         division, sales force]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "sales force":
   agent, clerk, floorwalker, sales agent, sales engineer,
   sales manager, sales personnel, salesclerk, salesgirl, saleslady,
   salesman, salespeople, salesperson, saleswoman, scalper, seller,
   selling agent, shop assistant, shop clerk, store clerk,
   ticket scalper