Hi I think Trimble Sketchup Make has a lot to offer for a free CAD package. Its quick easy to learn and well maintained. Its pretty hopeless for anything really organic but then that's unlikely to be what you need. There are also many free plugins which easily make up for any lack of functionality the free version has. Indeed using plugins you can make it into anything you really need. Its main focus is 3d Cad but it can be pushed to 2d. I teach this to 16-18 year olds and we prepare files for lasercutters and cnc routers using it and export using a free .dxf plugin.