Distributive bargaining always has a winner and a loser. It happens when there is a fixed quantity of something and two sides are fighting over how it gets distributed. Think of it as a pie and you're fighting over who gets how many pieces. In Trump's world, the bargaining was for a building, or for construction work, or subcontractors. He perceives a successful bargain as one in which there is a winner and a loser, so if he pays less than the seller wants, he wins. The more he saves the more he wins.
The other type of bargaining is called integrative bargaining. In integrative bargaining the two sides don't have a complete conflict of interest, and it is possible to reach mutually beneficial agreements. Think of it, not a single pie to be divided by two hungry people, but as a baker and a caterer negotiating over how many pies will be baked at what prices, and the nature of their ongoing relationship after this one gig is over.
