"Back in the olden days", I would just pirate Photoshop. I'm not condoning that and it isn't as easy as it used to be.
I will offer a few suggestions. First, if you aren't dead-set on "Photoshop" I would suggest looking at GIMP on Linux. It isn't photoshop, but it is still a powerful tool for photo editing. It is also FREE. Here is one big reason to consider it: You will learn photo editing, not Photoshop. Much like learning a language vs. memorizing some words in another language. You will acquire the core skill you need. Then, once you have some cash you can get Photoshop because it is indeed a superior product. Jumping into Photoshop after GIMP will seem like a walk in the park. In part because you learned the underlying skills and not just how to click buttons from a photoshop tutorial.
If that isn't your speed, look at just buying an old copy of Photoshop. Several years old is still plenty useful. You will also get some of the benefits you would have acquired from using GIMP. You will have learned it in a more fundamental way since you are using a "less easy" version.
Lastly, since you are a student see if you can get a discount from Adobe. I suspect you may still be locked into a contract, but that is an important thing to get used to with Adobe! ;)