mwave offers the refurbished TRENDnet Wireless USB 2.0 Adapter, model no. TEW-644UB, for $4.99 plus $1.99 for shipping. That's $6 under our June mention and the lowest total price we could find by $13. This adapter is purported to provide coverage of up to 164 feet indoors and 328 feet outdoors.

Note: A 180-day warranty applies, although it's unclear who backs it.