There is none. All major Linux certifications (LPI, CompTIA, RHCE, etc...) all cost money.
Ubuntu Linux.
Linux and the many variations based on Linux (Ubuntu, Mint, to name but two) are aimed at any one who wishes to use it, and is available for free.
Most Linux distributions are available free of charge, so they do not require q product key to install.
The question is unclear. Assuming you are asking usages of linux, well people use it for personal computing. Most of the companies use linux for servers. A Linux based system is free for anyone to use. A linux system distribution can be used in the same way as windows. Almost any application for windows has an equivalent application available for linux that does the same job. Linux has word processing, picture, sound and video edotors as well as their file format converters. It can be used to play many games, play song, watch videos. Linux is available for almost any personal computer available and almost any other computer in use. Most commercial network routers and firewalls are based on linux.
Yes, cloud computing exists for Linux users. You can use almost any of the platforms with Linux.
Yes, there are lots of free typing certifications. Try going to a night school or Continuing adult education center. These places are recognized by employers.
Completely free. If someone sells you Linux, it is legitimate, however, it will not be for a license to use the software. The GPL is not that kind of license. However, it is still free as in freedom, not free as in beer, meaning it is entirely valid under the GPL to sell Linux.
"Linux is a computer operating system, like Windows." "Linux is an OS, but the code for it is open source, meaning it is available to anyone and can be manipulated by any user."
Yes. Linux, to name one. You can buy a CD for the sake of convenience if you like, but several of the major distributions will let you copy it for free from their servers.
This is a question without a simple answer. If by "Linux", you mean the Linux kernel, then yes. The source code is available free of cost, and you are free to modify it with only a few restrictions. If you meant "a Linux distro", then maybe. Most Linux distros, such as Ubuntu, Fedora, Debian, and Slackware are available free of charge as well, and with similar rights to modify and redistribute. However, a few Linux distros, such as Red Hat Enterprise Linux or Xandros use a lot of proprietary software, and are not made available free of charge.
There are online training courses for Linux for the average user. You should ask people you know for online training courses that are available to the average consumer.
I don't believe any software in itself was a "catalyst" for Linux's success. Its very nature allowed existing applications to be ported to it fairly easily, and since it was free, it became a very attractive option.