Akodi via Amazon offers the Anewkodi AC600 Dual Band 802.11ac Wireless USB Adapter for $19.99. Coupon code "Q7WINB6Q" cuts it to $11.55. Plus, Prime members bag free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $8.02.) That's tied with our Black Friday mention and the lowest total price we could find by $1. It features a long-range 2dBi antenna and up to 600MB/s WiFi speeds on 5GHz and 2.4GHz bands.