Walmart offers the Samsung 50" 4K 2160p WiFi LED-Backlit LCD Ultra HD Smart Television, model no. UN50JU6401, for $698 with free shipping. That's $130 off and tied with our mention from two weeks ago as the lowest total price we could find. It features a 3840x2160 (2160p) native resolution, 4K upscaling, WiFi, Smart TV apps, Ethernet, three USB ports, and four HDMI inputs.
Update: Specs corrected.