Looking to replace my dayly driver with this 05 mustang from a local dealer. They are asking 12888 for it and KBB says the car is worth 11600. I know its normal that they start out high but whats the proper way to haggle them? Also, my old car is a 92 in perfect shape, better to hold onto it and sell privately or just throw it at them and take whatever they give. Sorry for the newb questions.