This library is for the RAD-0301 meter, marketed as a the co2meter.com mini CO2 meter. I don't know if it works with any other models but as I have one of these, I can tell you it works from my linux machines.
You're probably going 'Wow that's expensive for a CO2 meter when I can goto Aliexpress and get one for $10!' This is actually pretty cheap for a NDIR sensor which is what one should use for CO2 monitoring. The cheapo $10 sensors are all VOC sensors that require calibration and can be affected by airborne pollutants like alcohol.
I believe this is only 100ppm accuracy, the 5-10ppm resolution sensors are many hundreds of dollars. It's fine enough for casual air quality measurements.
For $20, you can get the MH Z-19, which is a NDIR type. You can talk to it over UART, and it comes in a 5000ppm and 2000ppm model IIRC. Decent documentation, and a good little sensor.
The S8-0053 looks interesting, but I have no experience with it. Also NDIR, boasts +- 40ppm accuraxy -- the room air might not even be that homogeneous...
The cheap ones are electrochemical, and they're not even that cheap.
Problem with it is that it autorecalibrates itself every 24hrs as far as I remember. It is a problem in room monitoring where you have constant high CO2- you'd have to take the sensor outside to fix it's reference level.
The core device is typically on the order of $50-$150 US, but with many of the sensors that CO2meter sells, you're also getting a microcontroller, display, power supply, etc. You'll frequently find temperature and humidity sensors and also barometric pressure sensors rolled into that, since NDIR is affected by all those things.
So the price of a good, fully realized NDIR CO2 meter is comparable with any low-volume, moderate precision, moderate complexity electronic device.
You're probably going 'Wow that's expensive for a CO2 meter when I can goto Aliexpress and get one for $10!' This is actually pretty cheap for a NDIR sensor which is what one should use for CO2 monitoring. The cheapo $10 sensors are all VOC sensors that require calibration and can be affected by airborne pollutants like alcohol.
I believe this is only 100ppm accuracy, the 5-10ppm resolution sensors are many hundreds of dollars. It's fine enough for casual air quality measurements.