As a student, you qualify for discounted software. (No one told you? Ask smarter people!) All you have to do is set up an account and scan your ID. Easy. Rhino is $1000 retail and $125 for students. This is a ridiculously sweet deal.
I recommend using Novedge for all of your educational software needs. Here is a direct link to V-Ray for Rhino, the best rendering engine for architecture. It’s $134 so, I say, close enough for your crazy low budget!
DO NOT download software that is pirated. The criminals who steal the software do not do it because they are nice people. You computer system will probably get compromised. I’ve seen students in my school have to buy a new hard drive and re-install their OS to get rid of malware & viruses.
EDIT. I just noticed that you are on a Mac. Unfortunately, you have far fewer options, as most plug-ins are not made for the Mac version of Rhino. If you’re serious about 3D, you might consider getting a used PC.