D-Link DWA-142 RangeBooster N Wireless USB 2.0 Adapter for $30 + $4 s&h - (View article)
dealmac.com
CompUSA.com offers the D-Link DWA-142 RangeBooster N Wireless USB 2.0 Adapter for $29.99. With $3.75 for shipping, it's the lowest total price we could find by $6. This 802.11n adapter supports WEP, WPA, and WPA2 encryption. [More]