is LINUX an open source operating system? is it available for free ?

Linux is free software. However, Linux is officially only the kernel (the core of the operating system).

When talking about the operating systems, they are called Linux distributions.

Most Linux distributions are free, but there are some that ask for a small contribution to get the stable release (like eLive). There are also enterprise distributions like Red Hat Enterprise Linux, SuSE Enterprise Desktop/Server, Oracle Linux, etc. which can only be obtained with a support contract.

A lot of popular applications are open-source and free as well. A couple that come to mind are:

Google Chrome, Firefox, Thunderbird, VLC, Opera, OpenOffice/LibreOffice, GIMP

These applications are all also available for Linux.

There are all kinds of Linux distributions you can download for free and use it on any computer you want to. Most distributions are under the open source licenses which means it is free to use, it is free to distribute, change, alter and modify to your needs and requirements by using the software management programs to install all the software and programs the distribution has in it's own file repository file system.

You down load the Linux .iso file, burn the image to a CD/DVD and then boot the computer with the CD/DVD. Most will run as a LiveCD which allows your to use it without ever installing it to a computer. There are several different ways you can Install Linux or use Linux.

Linux is Free and Open source software. Not only you can get Linux free, most of the programs developed for Linux are free software. There are nearly 300 distros of Linux. Try ubuntu. You can down load and burn a Live CD from www.ubuntu.com.

100% free forever.

Great answer from VenuG.

ya what he said