mwave offers the PremierTek PowerLink PT-H5DN 802.11n Wireless USB Adapter, model no. PT-H5DN-2770, for $12.99 with free shipping. We've seen it for a buck less, but that's the lowest total price we could find now by $6. It features a max speed of 300Mbps, 5dBi dipole antenna, support for WEP, WPA2, and WPA-PSK encryption, and more.