First one needs to determine what size air purifier is needed for the size room or home. Next is the cost of the purifier itself. Small units for a small room can cost as little as seventy dollars in store or online with free shipping. A medium size unit can cost one to three hundred dollars either online or in stores.
The much larger units for large rooms, multiple rooms or the entire home will cost more. A unit this larger can cost hundreds to even thousands of dollars. The need greatly determines size that is needed and how much one will need to spend on the purifier.