I'm just about to leave for a long international flight, so this is absolutely perfect for me!
Glad I saw the comment about it being paid so I could get to the purchase screen before I lost internet. (As a side note, it says "Buy now for $3.99" but it's really $5.99 in my currency. Not sure if you can make the button match to the price in the locale)
It is just a placeholder for the price in your currency. Sometimes the play billing library takes a little while to get the price from the server. If you swipe up the app from app drawer(force close) and open it again it should show the correct price in your currency.