I think it is great that you are helping out your friend
When i first read your post i thought of the simple school things pens, pencils but a really great idea would be to decoupage a notebook for her. You could get a couple notebooks cheap and then decoupage different things on to it. Her favorite things, maybe a picture of the both of you together, some quotes of inspiration.
( my favorite quote sites are http://motivationalinspirationalquotes.com/
Another cute and cheap idea is to make a little school survival kit. You would put things in it like Tissues - to wipe your eyes after sleeping during class, and cute things like that. There are some great ideas at this website http://www.craftygardener.ca/survivalkits6.html
, scroll down the page a bit to get to the student survival kits. You could also do a search with any search engine with the keywords student survival kit and it should bring up lots of ideas. Also don't forget to throw in some candy that's always fun to receive and even share at her new school as she makes new friends! Hope this helped!!! Good luck!!!!!