Just following the steps you can get a 2301 Amazon coins for Amazon App store and Free GTA: SA game which costs $6.99.
This is for United States Amazon Users only.
To get these
1. First visit the promotional page here
2. You can see five applications on that page.
Don't step the white tile
Food Network In the Kitchen
Strawberry Shortcake Bake Shop - Dessert Maker Game for Kids in Preschool and Kindergarten
Dr. Panda's Restaurant - FREE - Cooking Game For Kids
iHeartRadio - Free Music & Internet Radio
Each one will give you 200 Amazon coins for free. So you will get a total of 1000 Amazon coins for free.
Now buy Grand Theft Auto: San Andreas using the coins you have got (699 coins to buy the game). The purchase can give you another 2000 Amazon coins. So in total you will have 2301 Amazon coins and Grand Theft Auto: San Andreas game in your account for free.
You may also wanted to check this Free 5 USD Amazon App store credit