dealer

businessman, enterpriser, entrepreneur

buyer, marketer, purchaser

hawker, huckster, hustler, peddler (also pedlar)

retailer, seller, shopkeeper, storekeeper, vendor (also vender)

jobber, middleman, wholesaler

distributor, provider, provisioner, purveyor, supplier

merchant, trader, tradesman

auctioneer, concessionaire

black marketer (or black marketeer), bootlegger, fence, fencer, hustler, scalper, smuggler, trafficker

discounter, distributor, e-tailer, exporter, jobber, reseller, retailer, wholesaler

chapman [British], hawker, huckster, peddler (also pedlar)

salesclerk, salesman, salesperson, saleswoman, shopgirl

bargainer, haggler, horse trader, palterer