This program is completely free. You can download it at http://www.blender.org/cms/Download.13.0.html
Start by completing this tutorial:
Starting Off
Creating a Heart
Modeling a Simple Person
http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Penguins_from_spheres
Build a Line of Buildings
Octopus
Trebuchet
Tracing
Castle
The Vase
First Animation
Appending Materials
Make a Roller Coaster