for the first 2 years, any printing I needed to do I could do at school. it wasn't much, as most of my materials were online or in a syllabus and I didn't print stuff unless I absolutely had do. so I didn't really NEED one for the first 2 years
third and fourth year I did a lot of printing, scanning, and faxing for setting up away rotations, filling out residency hire packets, etc. If you could swing it and feel like it, an all-in-one might be a worthwhile investment. you can get in to them for ~$100