You can make your own to save money, I made this project for example. I paired it with an Air-1 sensor and home assistant to ramp up and down the downs in real time according to the live air quality readings.

https://makerworld.com/en/models/2470181-nukit-tempest-euro-...

Filters are included, as well as high quality fans, AC/DC converter and speed controller, and the portable/collapsible enclosure. It's really not that expensive vs trying to put together the parts yourself, and it's tested to work very well compared to other more expensive filters.