Trooperbay Gift Card

To redeem your gift card at check out:

Add products to the cart in the usual way, then tap Checkout.
Tap Gift card (if you don't see the Gift card option, then enable it from the Payments settings screen).
Enter the gift card number on receipt.
Tap Redeem.
If there's a remaining balance, then tap of the following options:
Tap Add payment to add another payment method.
Tap Done to return to the products screen.

The receipt shows the last 4 digits of the gift card used in payment, along with the remaining balance on the card.