There's a certain amount of drag and drop of primitive shapes in most CAD packages. However you then need to work out how to manipulate them: stretching, combining and occasionally having to adjust a cusp node.
The Inkscape program I mentioned above is FREE. It runs on pretty much any computer - PCs, macs, linux; and on very modest hardware. My desktop at home is an ancient Windows 7 PC. When you switch it on, go make a cup of coffee while the hamsters get up to speed! Inkscape is still very useable. If you are struggling to work out how to go something, there are loads of online tutorials.
Obviously if you've not used CAD before, it takes time to get with the lingo, work out the kind of things you can do, and how to do them. If you have a computer, the only cost is your time and patience. When you can weld shapes together, edit nodes, etc. pretty much anything is possible.