The World of Disappearing and Landlocked Books
Google Play might delete the ebooks you purchased from them if you visit another country.
Amazon may charge you the full price of a textbook if you rent one from them and take it over state lines. (This could affect a lot of my friends who attend school here in Chicago, but visit family in Wisconsin/Indiana on the weekends!)
We recommend visiting your local bookstore or library for all of your unshackled book needs!