If you want a cheaper, go with a Xiaomi one, but unfortunately you will need a RPi for the integration for the Mi Connector setup. There is a topic about it.
Philips produces as well smart models, they are quite decent, and more expensive. I have one with a humidifier and purifier, my wife insisted on that. It worth the investment. For integration, you again need a RPi again a way to feed some data to ST, there is a nice CLI for it called py-air-control. To call commands on the CLI, I believe there is a solution for that under the ST Anything umbrella.