Usually when a student joins a hagwon (private school) their textbooks are provided by the school so I'm guessing that your boss thinks printing and photocopying sheets are cheaper then buying a book. It means a lot more hassle for you and what do you do when the machine breaks down?? I have always been lucky enough that if I want a certain book, I talk to the boss and tell him how great this book is and that in America a lot of students use it..etc and then it's provided by the school in about a weeks time.
By the way who paid for the website? The boss or you?