There are many ways to back up your files...
1. You can save to a flash drive
The good: It is pretty easy, and flash drives are pretty cheap
The Bad: It is so so very easy to loose a flash drive
The Ugly: Flash drives can transmit malware and viruses between computers
2. You can save to google drive
The good: It is free and included with your gmail. Great for collaborative work.
The bad: It has limited space (especially for large graphics files) It really works best with google docs.
3. You can save to iCloud
The good: Many people already have this (included with apple phones)
The bad: Limits space, and file type. It is not free without a iPhone
4. You can save to DropBox
The good: It is free, and can hold a lot of files. You can get more free storage if you get friends to add dropbox!
The bad: You do have to try to add more storage. There is not enough with the basic account. (but add a few friends... :)