As one of its daily deals, Yugster offers the refurbished Linksys Mini Dual Band 802.11ac Wireless USB Adapter, model no. AE6000, for $16.97. Apply coupon code "FreeYugBuck" to cut the price to $15.97. With $5 for shipping, that's $7 below our July mention and a very low price for an 802.11ac WiFi adapter. (It's $14 under the best deal we could find for a new one.) It supports up to 128-bit encryption and up to 430 Mbps throughput. A 90-day Linksys warranty applies. Deal ends September 11 at 6 am ET.