Update from Ashwin
This promo should work in all Countries where the amazon Appstore is available it seems, as I managed to get the $5 Credited to my account.
To get the $5 Appstore Credit, open the Amazon Appstore app on your Android device and buy any free app of your choice. It should give you a pop up message saying the $5 has been credited to your account. You will also receive an email from Amazon confirming the same.
You can buy any app or game which costs $5 for free, this also works on In-App Purchases.
On this Holiday Season, Amazon will give $5 credit to use on Appstore. This is for all users who will download an app from Amazon Appstore today (December 24) or tomorrow (December 25). You need to use the latest version of Appstore, if you already have it on your phone upgrade it to get this.
Amazon will give you a paid app free everyday, to use the applications you will have to keep the Appstore application on the phone too.
Install App store
If you already have it make sure it is version 7.5 (“Settings” >>>“Version and Release Notes”)
Download any app or game from the Appstore. (a free one will also do)
You will be credited $5 with in an hour.
Terms and conditions
$5 promotional credit expires on March 31, 2014 at 11:59 PM (PST).
$5 promotional credit can only be used to purchase eligible digital products through the U.S. Amazon Appstore and may not be combined with other offers.
Read more here
See the images below on how to check your balance