While using the AH I noticed that the crowns can only go as high as 2 billion cr. Instead of 3 billion it goes to 300 million. Eventually by decoding the costs and what-not, I figured out the max. amount of cr is a very random number.
The max amount of crowns is 2,147,483,647. That's a lot of crowns.
it's not that random, it's because numbers in Java are typically 32 bits which means they are able to hold 2^32 different values.
But since they need 1 bit for sign (positive or negative) you get a range of -2^31 to 2^31-1 (which is the number you posted)