Is it really called „Unzip Tool“? Or rather (un-)archive software? Anyway, I guess you’re already aware of what I’m referring to. Since Mac OS X doesn’t provide the capability of extracting (or creating) certain archive types like rar or 7zip, you’d really need some third-party software for that.
It’s a good time to be a student! Usually, students (and teachers or other faculty staff) can already get interesting discounts from retailers and software companies like Amazon, Apple, Ableton, Adobe and Autodesk. But recently JetBrains also decided to give out their cool IDEs to students and educators for free. Same goes for GitHub which decided to not only give you a micro account for free for two years but bundled it with additional licenses for other platforms as well: they call it GitHub Student Developer Pack.
Just to complete the list: Microsoft is also offering lots of advantages for students. My school is for example giving out Microsoft Imagine (formerly DreamSpark) licenses to every student. That lets us download Microsoft Operating Systems and other Microsoft software for free (even new Windows preview versions or the Visual Studio IDE).