Colleges estimate cost of books as if you have to buy every book for every class brand new, (some base on the cost of the mandatory books for each class*the cost of the book at the campus book store) That’s not the case, however, some professors/classes do demand brand new text books (for one reason or another) which can cost in the realm of $60-$300 each. Some classes require multiple textbooks. Some degrees have a higher rate of needing brand new text books (such as degrees that require certain program codes that are included in the text book).

You can likely get away for most classes (Atleast undergrad) with used books/PDF versions that are much cheaper.

Campus Fees could be multiple different things, not sure what’s included at UC. I’ve seen other colleges (might be the case here as well) include the cost of Parking passes, campus services (such as a psychologist health clinic) mandatory funds for your campus identification card to be spent on campus. The list could go on and on.