This deal has ended.
Buy.com has this D-Link Wireless-G Desktop Adapter for Desktop PCs on sale for $21.99. This uses 802.11b/g wireless technology and works at speeds up to 54 Mbps. It's received 5 out of 5 stars from its first two reviewers. Shipping is free and there is no sales tax (except CA, MA, MD, NY, TN).