Walmart offers the Panasonic 55" 4K 2160p 120Hz WiFi LED-Backlit LCD Ultra HD Smart Television
in Silver, model no. TC-55CX420U, for $599.99
with free shipping
. That's tied with our mention from a week ago as the best price we've seen. (It's a current low by $39.) It features a 3840x2160 native resolution, LED backlight, 120Hz refresh rate, WiFi, Smart TV apps (including Hulu Plus, Netflix, and YouTube), USB, and three HDMI inputs.