The Levoit Core 400S air purifier, consistently ranked among the best, is currently discounted by $37 during Prime Day, bringing the price down to $183. While not the absolute lowest price ever recorded, it's a significant saving on a highly effective device. The Core 400S excels at cleaning the air in rooms up to 1,733 square feet within an hour. Despite a slightly cluttered app and less-than-perfect aesthetics, its performance makes it a top choice for improving air quality.