This article shows you how to apply discounts on a gift card purchase.
For more information on how to sell gift cards in general, please refer to: How to Sell a Gift Card
On the Checkout screen, enter the gift card value and tap on Set custom price.
Enter the discounted price.
Alternatively, you can also tap on Change Price Discount if you would like to add a percentage discount instead.
Tap on Go to Payments to complete the checkout as you normally would.