Question: How much did Avicenna pay for the book that helped him understand the Aristotle text?
Sentence: Forty times, it is said, he read through the Metaphysics of Aristotle, till the words were imprinted on his memory; but their meaning was hopelessly obscure, until one day they found illumination, from the little commentary by Farabi, which he bought at a bookstall for the small sum of three dirhams.
Answer in sentence: yes