Novgorod

Every five years you will get a popup that asks for money in the name of the golden hordes khan. If you don't have the money to pay the khan your in luck. Make sure you have an advisor that lowers revolt risk. You also need to whoop muscovy's butt in war. Later after the war there should be a popup that says that the khan is letting you off on paying the money from your agreement. You will then be able to save up ducats to wage war.