How do I redeem an iBooks free coupon? I remember a message after installing the iBooks app on my iPad telling me that I would have one free book to download. I never used it but now I am interested and wonder if this coupon is still active. 

How could I know without spending money accidentally?
Find the redeem code button in the iBook store.
Enter Your Promo Code
Push redeem button
After you entered your promo code, you will (hopefully) get a message saying that your item is downloading.