Quick question...looking to build my library for my classroom. Some books on amazon are listed for .39 used but then they list who they ship from. I was wondering if anyone bought used books before on this site? Does your credit card info only go to amazon or to who the book is actually coming from? Just curious. I started adding books to my cart then realized each one was being shipped from different individuals. Just not familiar of how it works Any feedback would be aprreciated.