auctioneer vs bargainer

auctioneer

noun
  • A person who conducts an auction on behalf of a vendor, taking bids to find the best price for the vendor. 

verb
  • To sell at an auction; to auction. 

bargainer

noun
  • A person who makes a bargain. 

How often have the words auctioneer and bargainer occurred in a corpus of books? (source: Google Ngram Viewer )