There is a student license available for CATIA which is cheaper than the commercial version. Their free CAD version is called DraftSight - once again a 2D version.
Going out on a limb here: There is a free operating system called CAELinux. This includes integrated software for 3D CAD, finite element analysis, CFD, pre- and post-processing, non-linear/multi- physics, 3D meshing, Matlab equivalents, etc. Basically all the stuff to get an Engineer excited.
It depends largely on what kind of CAD you are looking for.
If you are looking for mechanical engineering / product development CAD, then there are some very good products our there. Locally PTC's Creo is widely used and skills are in very high demand.