Promo codes are entered upon checkout, and are available on both the app and web versions of PangoBooks.
When you are ready to buy a book, proceed to the checkout screen, where you should see a dropdown titled "Pay With PangoBucks". To add a new promo code, click "Add a promo code" and enter the code. This will add the value of the promo to your account and select the "Promo" option in the dropdown!
Please note, promo codes do not discount the price of your order - they add credit to your account! Additionally, please note that each promo code has a different minimum requirement for usage. If your cart does not qualify for that promo code, a yellow message will pop up to let you know! If you apply your code during one checkout but do not use it for that purchase, make sure to click "Promo" as your payment method at your next checkout so that the promo value is applied.