mwave offers the PremierTek PowerLink Hermes 300Mbps 802.11n Wireless USB Adapter with Dual 9dBi Dipole Antennas, model no. PL-18N, for $29.99 with free shipping. That's tied with our June mention and the lowest total price we could find by $2, outside of the price below. (Most merchants charge $38 or more.) It features a max speed of 300Mbps, operating distance of up to 1.2 miles, purported 10x signal strength and 1000mW power output, dual 9dBi dipole antennas, and support for WEP, WPA2, and WPA-PSK encryption.

A close price: HometownTV Plus via Amazon charges $30.69 with free shipping.