If you are a individual student or faculty you can get most of the Autodesk products for free from the Autodesk Education Community. There is really no catch as these are the full Autodesk products and the software license is for 3 years. Included are AutoCAD, 3ds Max, Maya, Inventor, Revit and many many more. You will also receive 25Gb of Autodesk cloud storage. 
http://students.autodesk.com