mwave offers the refurbished EnGenius 802.11n Wireless USB Adapter, model no. EUB-9706, for $9.99 with free shipping. That’s tied with our February mention and $13 less than the lowest total price we could find for a new one. It features WEP, WPA, and WPA2 encryption.
A 30-day warranty applies, although it’s unclear who backs it.