There's actually a program called 'FreeCAD'. It is basically an 'inferior good' which can be used as a substitute for Solidworks (in case anyone's wondering, I'm currently studying Economics for the first time in my life and therefore applying it to nearly everything). There are some very interesting videos on FreeCAD on YouTube. The type of work I do is far removed from Mechanical Engineering so I likely won't use FreeCAD or Solidworks in the foreseeable future.
I mostly use regular 2D CAD. I am currently trying out a 2D CAD alternative called GstarCAD. It's NOT free but much cheaper than AutoCAD. Haven't used it long enough to give a solid recommendation but I like it so far. There are a lot of CAD programs that aren't AutoCAD but are similar to it. Draftsight used to be free, now it has a yearly fee and isn't that great value wise. BricsCAD is another alternative but is actually quite expensive as far as alternatives are concerned.
Any 'Autodesk' software (AutoCAD, Revit, Inventor, etc...), usually offers a generous student licensee arrangement. They appear to be tightening up their restrictions as it pertains to who actually qualifies for a student license and who doesn't. And this includes checking up on student license holders (a lot of people are using student licenses commercially).
It's worth mentioning also that there is a really good 3D surface modelling program called 'Blender'; it's completely free and actually works better than paid programs within it's own little niche. Cools stuff!!
