Northern Tool offers the Tjernlund 2-Fan Crawl Space Air Supply Fan for $99.99. Coupon code "260475" cuts that to $79.99. With $8.49 for shipping, that's essentially tied with our mention from last month and the lowest price we could find by $26. It installs on inside or outside passive crawl space vent openings, features a freeze protection thermostat, and delivers 220 CFM. Coupon ends August 31.