https://www.woot.com/offers/winix-c545-4-stage-wifi-air-purifier-carb-18 Winix C545 4-Stage True HEPA WiFi Air Purifier w/ PlasmaWave Technology (Factory Reconditioned) on sale for $49.99. Shipping is free for Amazon Prime Members (must login with your Amazon account and select a shipping address in order for Woot to apply free shipping) or is otherwise $6 per order.