In order to take advantage of the buy 2 get 1 free offer, you have to include all of the books in your order at the time of checkout. All of the items MUST be from the BUY 2 GET 1 FREE tab on our website This also applies to the BUY 3 GET 3 FREE option. This offer can be applied multiple times per order (add 3 books to your cart, one of the items will be discounted. Put 6 items in your cart, 2 of the items will be discounted, etc.) An example picture is below.
It is stated on our website under the Buy 2 Get 1 Free Exclusives tab:
Example of applied discount (if your cart does not look like this, the discount has not been applied and you may have chosen items that do not apply for the discount):