Amazon is selling the Coway 1512HH Mighty Air Purifier w/ True HEPA for $166.08.
The Sweethome rates this as their pick for best air purifier. I was looking for one of these when the Northern California fires were billowing smoke across the area.
I ordered three days ago at $209 and re-ordered today at $166. Not a bad price if you're thinking about or in the market for one.