Seriously, you could have learned one of the 3D programs by now. Pick one of the standard ones and go for it.
SolidWorks has a one year student license for $139 here in the US (probably a similar discount elsewhere in the world). That’s extremely cheap for the power it has. That’s also less than a student one year license of MODO.
Rhino for Mac is 100% free (as others have said), and for Windows you can use the demo for 25 saves for free to see if you like it. Then it is $195 US for a non-expiring license that you can upgrade to a commercial license later.
Alias (not quite as widely used in ID anymore, but amazingly powerful), also free if you are a student!
Just pick one of those three. They are the three industry standards for ID, if you want to make real products, in the real world…