You want to buy her what is euphemistically known as a "beater bike". That means a used bike that it is safe to ride but looks like crap. If it is locked outside in all kinds of weather in a place with a real winter (snow and rain) then you will not be so upset when it suffers the effects of being outside. I used to work at a federal facility on the UNLV campus and we had a summer student from the Midwest bring his bike to campus for getting back and forth. It was securely locked outside a dorm and gone within three days. If you want to read an interesting article about the campus where I once was a student, read this:
https://uwpd.wisc.edu/news/uwpd-seiz...likely-stolen/. I would not buy a brand new shiny bike of any price for use at college. BTW, that same federal facility where I worked had a locked bike compound but my own beater bike, a $20 Motobecane Mirage disappeared one day. One of the maintenance workers decided it was abandoned so he cut the lock and took it home. I still had the front wheel in my office. I got it back but without a front brake because the thief took off and threw away the front brake when it wouldn't work with the wheel he used as a replacement.