Chrome OS is an operating system designed by Google that is based on the Linux kernel and uses the Google Chrome web browser as its principal user interface. As a result, Chrome OS primarily supports web applications. Chrome is very stable and very secure. It is perfect for an individual or group that uses Google apps or other web apps.
When using Chrome OS the user never nor the web has access to the kernel there is no vector to install malware of any kind making Chrome OS far more secure than Windows or Apple computers. If you ever have some sort of problem it is easy to wipe it and start over having never lost any data.
Because Chrome OS is free and will run on almost any hardware with 2GB of RAM you can find Chromebooks (portable computers running Chrome OS) for much less than $200 at the low end. The are now many higher end computers with better hardware running Chrome OS some costing as much as $1000. There are many Chromebooks and Chromeboxes (desktop computer running Chrome OS) made by many manufactures at ever price.