At the University of Granada – Modern Languages Center you will not have to buy a book to follow the classes, with a few exceptions. The professors prepare their own material which they compile in dossiers. They also uses audio-visual media to teach his classes and make learning easier. You, in class, will have to take notes from the professors explanations. This dossier, prepared by the teacher, can be purchased at the Center at a very low price.
Having said that, some courses require that you buy books to read as part of your homework. For instance, Literature courses. You can buy these books in a bookstore in Granada, but you can also go to the Center of Modern Languages library.
However, the Intensive Spanish Language Program requires students to buy a book to follow the class. It can cost around 25 euros. But just like reading books, try to find them in the CLM library before spending the money.
As for notebooks, pens, pencils… Normally in Spain we write exams and exercises for classes with a blue or black pen. But the professors at the Center of Modern Lanauges, are used that students from the United States use a pencil for almost everything. I would generally recommend that you buy your notebooks in Granada instead of coming all the way from the United States.