On average, indoor air quality testing costs between $250 and $300. Mold and moisture assessments will cost $295, and radon testing will cost $135 to $150, but you may be able to get it for a better cost if you combine it with a more complete, and more extensive, house inspection report. You can also purchase your own monitor. These gadgets are available online and can run anywhere between $50.00 to $1,000 for higher-end monitoring.