Granted--there are many distros that do not have a for-pay version, but the fact that several of the big boys DO, puts the lie to the claim that Linux must be free-as-in-beer.
The whole point of Linux is not its price point--the whole point is that you, the customer, have direct access to the source code. Thus, when something isn't working quite right for your installation, you have the power to fix it--on the spot, rather than placing a call to tech support.
It's not free to run or support--you need the expertise for that--just like you do for Windows.