Walmart offers the refurbished Vizio 55" 4K 2160p LED-Backlit LCD Ultra HD Smart Television, model no. D55U-D1, for $409.99 with free shipping. That's $60 under our September mention and the lowest total price we've seen. (It's $188 under the current cost of a new one.) It features a 3840x2160 resolution, 802.11ac wireless, Internet apps (including Netflix, Hulu Plus, and Amazon Video), USB, and five HDMI inputs.
Note: No warranty information is provided.