Amazon offers the TP-Link Archer C5 802.11ac Wireless Dual Band Gigabit Router, model no. C5 AC1200, for $67.95 with free shipping. (B&H Photo Video charges the same.) That's $12 under our May mention and the lowest total price we've seen. (It's a current low by $2.) It features four Gigabit ports, two USB 2.0 ports, simultaneous 2.4GHz and 5GHz frequencies, and two external antennas.
Update: Specs corrected.