Dealerships aim to make as much profit as possible by either maximizing their profit margin or by reducing their costs to a minimum. In a negotiation, the initial offer a dealer will present will be the figure that best optimizes these two factors. You will need to figure out whether the dealer is more willing to take less of a profit by lowering the price of the car, or more of a cost, by negotiating a higher trade-in value. It also depends on the dealership, the timing, and popularity of the car.