Link: AutoCad Alternatives
Opensource.com frequently publishes materials on open source alternative to major commercial products.
Since some of my readers may not be techies, let me note that open source software provides free and open access to its source code, so that anyone who knows how can compile and create the program. Someone can also, according to whatever open source license is applied, modify or even create a new branch from the source code, usually if they provide the source code for their work in turn. There are a number of products available commercially that are open source, and one can either buy the commercial product or use the community edition. My company Energion Publications, of which Neufeld Computer Services is a part, uses Odoo in its community edition on our own server as our accounting application, and we allow open document format for manuscript submissions.
With that introduction, I want to link to the opensource.com article on AutoCAD alternatives. With the cost of CAD software, potential users would do well to see if these options might serve their needs.