Ubuntu is what led me back to Blender.  I tried Blender in the past and couldn't get the hang of it.

In March this year I downloaded Ubuntu (free, BTW) and liked it so much that I have it on 2 of my PCs and on my laptop.  I've only kept Windows on one machine, and only because of Poser, which doesn't run well under Linux (for me, anyway).

But I've decided that I like Ubuntu so much that I'm going to ditch Windows altogether. That means no more Poser, so I've been forced to try a bit harder to learn Blender.  And so far, I'm loving it.

I've found that Ubuntu is faster on a slow machine than XP on my fast machine.  When I go back to my Windows computer, it feels slow and clunky now, just as Poser feels slow and clunky compared to Blender.

For me, Ubuntu and Blender are going to be the way forward, so far as any 3D work is concerned.

PS - the Linux licence means that that it's available free, but it's not illegal for people to sell it (if they can find anyone willing to pay for what they could get for free!)

In free/Open Source software, the 'free' is generally taken to mean 'free as in free speech, rather than free as in free beer.'  But it does generally tend to be free as in free beer too.

You'll find the best definition of 'Free' software at the website of the Free Software Federation, HERE.