RE: Advice for an oldie newbie
There's a great sticky thread at the top of this forum's listings that discusses the pros and cons of most of the available cheaper options as well as some hints on how to use them. In particular the Baker's Dozen tips I wrote up for TurboCAD in particular and all CAD's in general. Have a read of those and see what you think and if you have any specific questions after that.
It's a long uphill learning curve and I suggest you draw up some simple stuff at first to just play with the CAD program and get used to the tools. Perhaps design a simple all balsa chuck glider or two just to learn the program and then move on to a simple trainer or Stik like sport design.
Once you get the hang of it you'll never go back. And older copies of TurboCAD are going on ebay for as little as $10. Get anything from version 7 and up and you'll be really, really happy. I think 9 and 10 are around $20 generally.