Rhino (educational) is fully functional at $149 last time I checked. There's a downloadable demo that you can run a million times if you want to learn and there are downloadable tutorial files as well. The demo will let you save only 25 times though, so keep that in mind.
I have used SW and Rhino and love them both. I use Rhino every day.
It can be overwhelming to try to learn. I recommend downloading Rhino demo and all of the tutorials. Go through them one by one no matter how basic you think they are. They build foundational knowledge that's very important down the road.
FWIW, I run the Windows version on a MAC with VMWare Fusion. There's also a MAC native version but I've not used it.
Here's a link to the demo...
...and here's a link to the tutorials...