This offer is valid for gift card purchases TODAY only. The terms state “while supplies last”, so I suggest purchasing sooner then later as the offer might sell out. You are limited to 1 promotional credit per account. Go to this site and click the “Click to qualify” button to take advantage.
The $5 promotional credit will be applied to your account within 2 days after your Amazon.com gift card purchase is complete. The promotional credit must be used by August 26, 2017 and is only valid on items sold through Amazon.com (not third-party retailers).