I will not be giving advice on selecting a VPN or explaining their uses, but suffice it to say many students use VPNs for a variety of reasons. In doing so, you are exposing yourself to a lot of risk.
A VPN redirects all of your online activity, but in doing so has the ability to see everything you transmit. If your connections are encrypted, you are in slightly better shape, but a VPN provider (yes, any number of those random apps that you can find in the app store) has the power to do whatever they want with the data you transmit. They can record it, sell it, redirect it somewhere you aren't expecting, track what you do and build a profile on you, or anything else (some interception attacks, called Man in the Middle, when combined with a phishing attack that's harder to see through a VPN, could collect your login info for your social media profiles and then that could be given or sold to someone else). Some of those apps are actually developed and operated by companies, hackers, or governments in other countries with the express intent of harvesting your information and selling it later. This gets particularly bad when credit card numbers and your email login (which all of your other accounts are probably tied to) get involved.
VPNs can read, store, redirect, and modify anything that you transmit or receive.
Ensure that you research the VPN that you choose to use if you do decide to use one. They do have their uses, including encrypting your data when you're in public places so that others on the same network (e.g., at the store or a coffee shop) can't read your data, but they come with definite risks. Do your homework. This applies to any online service you choose to trust; they have your information and can do whatever they want with it. Make sure they have a reputation to uphold and that someone who knows what they are doing and looking for has checked them out.