If your using this stuff as a hobbyist and not for commercial work, you may as well sign up to Autodesk's educational program. Then you can get the full versions of all their software free. with no limitation apart from watermarks on Inventor and Revit's 2D technical drawing output (and a dire warning on start up about what will happen to you if you use the products for commercial work).

Fusion is included as part of the Inventor Pro package.

If you want to explore the ultimate in free form A-Class surface Nurbs modelling, try Alias Design. However the learning curve is almost vertical and the UI is worse than the original Blender. Trying Alias will probably convince you that MoI is better suited to what you want to do, unless you design car bodies for a living or need G3 continuity in everything. The Alias Design series is a good example of why Michael's approach to having simplified commands is important

However, for those looking for a free renderer for MoI, Max and Maya include Mental Ray and will import models from MoI.