I learned to haggle from a master. He collocted old fishing reels and pretty much anything to do with fishing. He would probably roll over in his grave if he saw me now because I really don't haggle much anymore. One important thing he taught me was to be prepared to walk away from a deal. Set your price and don't go over it even if it hurts. In his later years he was far more gentle in his negotiations, many times paying more than the asking price if the person didn't have a clue about the real value and was nice.
Most people appreciate the honesty and I think treating people decently does come back to you.
Rodney