Walmart offers the Vizio 50" 4K 2160p WiFi LED-Backlit LCD Ultra HD Smart Television model no. D50u-D1, for $598 with free shipping. That's the lowest total price we could find by $41, excluding the mention below. (For further comparison, most stores charge at least $702.) It features a 3840x2160 resolution (4K), 802.11ac wireless, Smart TV (with access to Netflix, Hulu Plus, Pandora, and other Vizio Internet apps), USB, and five HDMI inputs.

A close price: Best Buy via eBay offers it for $599.99 with free shipping.