My Guess is that you are from Australia. The AUS Dollar uses the $ symbol and is currently Trading 32 cents higher then the American Dollar. That would explain why you would see that dollar difference. I am assuming this is where you live i have not clue. Or the google account you are using has the home address set in the AUS location.
That wouldn't explain why in-app purchases in other games are showing correct amounts though. In other words, it is possible to have it shown correctly despite exchange rates or whatever is causing this, which has been my point since the beginning even though idiots like korvas128 are trying to make it into some conspiracy.
And no, I'm not in Australia.