Don't rely on professors, folks. If you want to know something, nothing stops you from pursuing the autodidact method except your self-motivation. Forget staring at screens, and studying some professor through an eye-glass! That professor you listen to may certainly have mastered his/her discipline, but beyond that he is a common dilettante. Expertise is for the narrow-minded - with the Internet, we should all have the ability to become rich and diverse polymaths of human knowledge. Expertise is merely a piss in the ocean in comparison to a life lived broadly, in examination of all that attends your interest. We're taught to believe that the "jack of all trades master of none" is a terrible dictum, and perhaps it has its flaws, but I am not arguing such an old point. I am arguing that you need to develop your mind beyond the discipline you choose for yourself. No professors will help you to do that - you must be true to yourself.
And on the question of books...its called a second-hand book store, or better yet, an online second-hand bookstore such as BetterWorldBooks.