Best Buy offers the refurbished Apple AirPort Extreme 802.11ac Wireless Base Station, model no. ME918LL/A, for $99.99 with free shipping. That's $29 under our refurb mention from September (which had an Apple warranty) and the lowest total price we could find. (It's $80 under the best we could find for a new one today.) It uses 802.11ac WiFi technology, which offers up to 40% faster transmissions than 802.11n.
A 90-day GeekSquad warranty applies.