Ebay offers Refurbished Dyson HP09 Hot+Cool Formaldehyde Purifier for $390 (reg $850) with free shipping.

Product Description:
Dyson's latest purifiers combine intelligent sensing with an advanced filtration system. Three phases of purification sit within a fully sealed filtration and airflow system. So what goes inside, stays inside.⁶ A solid-state formaldehyde sensor and a unique catalytic filter detect and continuously destroy formaldehyde.¹ Then powerful Air Multiplier™ technology purifies, heats the whole room and cools you.²

• Third party full machine testing based on GB/T 18801-2018 formaldehyde cumulative clean mass testing with continuous injection until plateau of formaldehyde CADR is achieved. Results may vary in practice.
• Tested In maximum setting for air projection, tested in Auto mode for purification coverage, tested for room heating per relevant Dyson method DTM961.
• Requires device to run app, Wi-Fi or mobile data, Bluetooth 4.0 support, and iOS version 10 or Android version 5 (or above). Standard data and messaging rates may apply. Refer to the MyDyson™ app for compatible voice services.
• Not applicable to heating
• This machine is compliant with safety standard UL 1278, as required by the US government. For this reason, heating and temperature control are not available in the MyDyson app. Please use your machine’s remote control instead
• Particle challenge by DEHS oil specified in EN1822 within a chamber specified in ASTM F3150.
• Fan; not air conditioning unit