Walmart offers the refurbished Sharp Aquos 65" 120Hz 4K 2160p LED-Backlit LCD Ultra HD Smart Television, model no. LC-65UB30U, for $529.99 with free shipping. That's $470 under our May mention of a new unit and the best deal we've seen for this TV in any condition. (It's also at least $818 less than you'd pay for a new unit.) It features a 3840x2160 (2160p) native resolution, 120Hz refresh rate, LED backlight, WiFi content streaming (Netflix, Youtube, Pandora, more), USB, and four HDMI inputs.
Note that no warranty information is provided.