What is the difference between using credits and purchasing for retail price?

First, over 90% of the eStories are available for credit. If you find a title that is only available from our publishers for purchase, then the credit option will not be displayed. As a member, if a title is available for credit purchase, you will be offered that option as well as the option to purchase it at the retail price, less your 33% member discount. If you would like to purchase a title for credit but have already used your available credit, we offer an extra credit pack for purchase, or you can consider a plan to provide you with more books.