Interesting section this one. I have a craft robo which I haven't done much with yet and also have access to a laser cutter occasionally but have been limited by my abilities with CAD type software. I bit the bullet recently and bought turbo cad 16deluxe from that well known auction site for less than £20 including postage.
I have spent some time on YouTube watching some excellent tutorial "films" , and would recommend them to others. Some of the best are by a chap called Paul Tracey which go through setting up the main page, menu options etc, and continue on to using it. If you type in "turbocad" in the search on YouTube they will come up. I suspect a lot of the other CAD programs will work in similar ways so the videos will be of use to others as well.