Kia dealerships near me (Spartanburg, SC)

I've been looking for a Frontier for a year or so (across the country) and I know prices and especially the value of my 2010 Tacoma!!!. And my son owns a salvage dealership in Charlotte wherein he buys units on the internet sales sites weekly. SOOOOOOOOOOOOOO do ya thunka we know values!!!! This guy at Benson offered me 6K$ less on a trade in than the bare minimum value of my truck. I would have tried to negotiate with him but I felt even after I shared my pricing and value knowledge he insulted me with his trade in offer!