If it is auto cad, Can I go to your school?
Better actually, I use Autodesk Inventor. All the features of regular CAD programs plus a great 3D implementation, parametric modeling, simple project management and even more complex plugins like stress brown townysis.
Have you asked your school yet? if they don't have it, they can arrange it through the Autodesk website. Not sure if they have to purchase a license first though.