If you don't mind cloud storage, OnShape is free for non-commercial use, well featured and easy to use.
I'd love to love FreeCAD but it suffers from the all too common problem with open source stuff, that the people who develop it are coders – they like writing code, they probably do it for their day job and are doubtless very good at it, but they aren't interested in user Interface design, user workflow, producing the documentation, etc.
Furthermore, many individuals work on this kind of project, and this can mean that there is no overarching design ethos to the thing, just loads of disparate modules which all do things differently.
This is what you're paying for with commercial software – they have people who specialise in UI, they have technical writers to write the manual and so on. If there's a free version, then that's all the better.
Note – I'm not slagging FreeCAD off, I think it's good, and tremendous that people make the effort to develop it, and if OnShape went payed-for only, I'd probably go back to it. Fusion 360 isn't available for Linux so that would be out of the question, plus its produced by Autodesk, who killed Softimage XSI, the best 3D animation program ever (and a model of good interface/workflow design), so it's it out of the question on principal.