linux free!! then how developers make money

i am a new user in linux
and when i installed linux
i was happy as if ive conquered someone unconquerable yet popular ..............
but same as wat other peole might have thought as a new user i thought
that how the developers at all made money if linux was free??
That's what most newcomers think.
But i then found out that these companies which sell open source softwares make money out of professional support or charging for the software.

Another point is that Open Source and Free are two different things. An open source software is just whose source code is public. A free software is one in which you have access to code, allowed to modify,use, tweak and distribute it all over.

There is a company called phpFoX which makes social networking software. Its open source but charges customers $300 for their software. Its not free, if you distribute it after changing the source code or use it without paying, it would be piracy. They just release the source code so that more bugs can be fixed or people can more easily make third party modules.

Most of the Open source Software companies like RedHat which makes its distro RHEL is free and open source. You can take its source code, compile the whole distro and start using it, though it still charged. They wont give you a compiled distro without a license payment.

CentOS is a linux distro which is completely based on RedHat, it just takes its source code and compiles to build the distro, its not piracy as RedHat is free software.

Most of the open source and free software makes make money by selling professional support. Its a truth and a fact that most of their customers want support. They dont worry about money, they want a stable OS and proper support to runt their business.
Most of the good companies do but licensed softwares as they wont want to get humiliated by being caught in piracy which might ruin their ambitions.

Even if you sell a software in say $400 instead of $300. but provide excellent support then its worth more than selling the software in $250 with horrible support, the situation worsens if there is a good competitor to you in the market...