mwave offers the refurbished EnGenius 802.11n Wireless USB Adapter, model no. EUB-9706, for $11.99 with free shipping. That’s $8 under our September mention of a new one and $11 less than the lowest total price we could find today for a new unit. It features WEP, WPA, and WPA2 encryption.
A 30-day warranty applies, although it’s unclear who backs it.