Yeah, same thought. Something like the Coway air filter ( https://www.youtube.com/watch?v=zxiDrEnjYEo ) regularly sells for under $200, and it is going to be much quieter than this option. It also has been tested fairly extensively from what I've seen, it's EnergyStar approved, etc, and it has a built in sensor. It doesn't look too bad either.

But I understand the point, especially in times when you can't find a purifier.

Also, good video on all this: https://www.youtube.com/watch?v=kH5APw_SLUU