The Alchemist has sold more than 65 million copies and been translated into 56 languages. A huge bestseller, in short. Here it is unabridged and free on iTunes. I am not sure how long this offer will last. So I would grab it sooner than later -- and while you're at it, don't forget to look through our collection of free audio books.
NOTE: iTunes is no longer giving away The Alchemist, but there is a way to get it for free from Audible.com. Details here.