How about "The Best Book on the Market: How to stop worrying and love the free economy" by Eamonn Butler. If only for the title.
Pick something written by von Mises.
"The Road to Serfdom" by Hayek. What was true last century is still valid today--if not more so!
I would go with a book that uses case studies to outline which institutions lead to economic growth and development.
No, not Powell's book. O'Rourke's.
Why not the print edition of the latest Economic Freedom of the World Index (or is that too obvious?!)
Here's the less obvious, yet best choice: Adam Smith's Theory of Moral Sentiments.
You cannot go wrong with Economics In One Lesson. A great introduction to economics and something students will be able to read and understand.
Should it be a book the library won't likely have already? How about The Mystery of Capital? Or Economic Sophisms?