I need a "cheap" software program for designing my Maker Pipe projects. I am using an iMac computer. What design software are people using?

Fusion360 is free for non commercial use. I will tag you on the post containing the step files for our connectors that you can use for designing. Hope this helps. 

I am probably the wrong person to ask, but I use SketchUp Pro, which is spendy, but is part of my general woodshop toolkit.