Amazon offers Prime members the Optimus Infrared Quartz Radiant Heater, model no. H-5210, for $19.99 with free shipping. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping adds $8.74.) That's $7 under last week's mention and the lowest total price we could find now by $8. This energy-efficient heater features cool-touch housing, two heat settings, and more.