Engines are _not_ free to play. They are no games. They are just a way to _make_ a game (and other 3D software.)
I don't know what you mean by teeth free. Maybe translation error?
Well. All the game engines (they are in fact not MMORPG engines - but you could also make one with them) you list here have a good documentation and can be used commercially (have to pay though.)
I do not think that there are good free game engines which you can use commercially without paying (as for documentation, opensource, community, active development,...). The best you can get is to use different engines for the different parts. There are free graphics engines (e.g. Ogre3D, Irrlicht,..), free physics engines (Bullet, Newton,...), free sound engines (cAudio,...) and so on.
If you are a beginner, you should just start to make small 3D applications and see, what parts you need. After a few applications, you might want to put together your own small game engine which will contain all parts you frequently use.
If you want to have a free ready2use game engine no matter what, see this list:
List of game engines - Wikipedia, the free encyclopedia
If you have never made a game, I suggest trying to make a pong or snake clone with WinAPI (make a window and use it as canvas) or some easy framework like SFML first.
Also making 2D games can be a help, since they are a lot easier to complete. But well, whatever - there are thousands of threads out there telling you this in greater detail^^
