SE tries to keep the price of houses relative to the amount of gil in circulation, so that the value of the house, compared to the value of gil, is roughly the same across servers. This means that you should not compare the price in raw gil, but compare the price in other things instead. Check how much is the price of, say, a piece of Coke in your server, and check the price of Coke in another server. The price of the same house in the respective servers should allow each player to buy the same amount of coke in their respective servers.