I agree with most here about the free software. 

If you want to do modeling you could look at sculpting and retopology.  I myself got 3d-coat (I couldn't afford zbrush) but it has some unique things to it as well.  I know blender has sculpting tools well.  You can download a demo of 3d-coat or go to the website and see some things it does.  I have the apps you listed plus Carrara Pro and am working on an applink from Carrara to 3dcoat. There is already goZ from those apps to Zbrush.

A lot depends on what you want to do.  You might look at some good tutorial courses too depending on what you want to render, like lightmaster or such.