For those who have
Monument Valley, which was free on 11/19/2014, there is an
In App Purchase add-on
Forgotten Shores for $1.99 or 199 Amazon Coins. The purchase of
Forgotten Shores earns 199 coins, so it's effectively free.
You may have to update the app first. There should be a notice that there are more levels available (sorry, I don't remember the exact wording). Assuming that you've installed
Monument Valley from the Amazon app store, when you choose to buy
Forgotten Shores you should get the option to buy it with either Amazon Coins or real money.
Source:
Slickdeals