Not being able to purchase with a debit or credit card has really made it hard for us to use the app the way WE the USER want to. Making us purchase "credits" is not reasonable for the everyday worker who don't make much and want to purchase one $9 book but having to pay $39.99 for 3 credits. I understand that gives me 2 more books but if all 3 books are cheaper then the actual credit cost how does that make sense? Unfortunately after 26 books im going to have to stop using this app.