Walmart offers the refurbished Vizio SmartCast E-Series 54.6" 4K 2160p LED-Backlit LCD Ultra HD Smart Television, model no. E55U-D2, for $399.99. Opt for in-store pickup to drop it to $390.79. That's $159 under our mention of a new unit from February and the lowest price we've seen for this TV in any condition. (It's also $156 under the best deal we could find for a new unit today.) It features a 3840x2160 native resolution, 4K upscaling, Chromecast (with access to Netflix, Hulu Plus, YouTube, more), four HDMI inputs, and Vizio SmartCast capability, which allows you to use your smartphone as a remote via the SmartCast app.
A 90-day warranty applies, but it is unclear who backs it.