The Honeywell Tabletop Air Purifier is now at Buy.com for just $46.99. This can handle 8.5 square feet of space and features a permanent HEPA-type filter that helps remove 99% of dust, pollen, tobacco smoke, pet dander, and mold spores. It's received 4.5 out of 5 from its first eight Buy.com reviewers. Shipping is free and there is no sales tax (except CA, MA, MD, NY, TN). TheNerds.net has it for $48.99, but they charge $10 for shipping.