How much does this cost to the nearest dollar?

Corentium Home Radon Detector by Airthings 224 Portable, Lightweight, Easy-to-Use, (3) AAA Battery Operated, International Version, Bq/m³
This version is in Bq/m³ and is intended to be used outside USA. In USA the measurement unit is pCi/L. The Corentium Home by AirThings radon gas monitor is a state-of-the-art measuring instrument that combines ease of use and performance. The Corentium Home by AirThings monitor allows you to take a reading of the radon levels and its LCD screen displays the average daily, weekly and long term concentrations. Powered by 3 standard AAA batteries, the monitor makes it easy to take measurements from one room to another in order to get an overview of the concentrations of rad

Price is $139.00
Price: $138.99