Just found this deal.
Buy an Amazon US gift card over $50 and get a $15 credit on your account.
Can only be used on Amazon.com
"A $15 promotional credit will be automatically applied to your account and emailed to you within three (3) days after shipping."
Updating the terms of this offer for clarification
Exclusively for new gift card customers: Get a $15 credit when you purchase $50 in Amazon Gift Cards
Enter promotion code 19GIFTCARD at checkout, or tap the button below to automatically apply promotion code to your account.
How it works
a. Tap the “Add the code to your account” button above or enter the promotion code at checkout.
b. Add $50 or more in Amazon.com Gift Cards to your cart, and complete your purchase.
c. Your $15 promotional credit will be applied to your account within two days after your qualifying Amazon.com Gift Card purchase is completed or, in the case of physical gift cards, shipped.
Offer ends at 11:59 p.m. (PT), December 22, 2019 while supplies last.
Offer has a limit of one Amazon.com promotional credit per account.
For complete promotion terms and conditions, please scroll down on this page.
How to Use Your Promotional Credit
Add one or more products sold by Amazon.com in new condition to your cart.
Complete your order by February 06, 2020, 11:59 PM (PT).
The savings will be reflected on the final order checkout page.