Bukkit

How It Works

Simply put, when a player changes world, MWM stores the player's old balance and replaces it with a new one for the new world.

Background on Economy Plugins

Economy plugins enable players to buy, sell, pay and bank with money or currency, e.g., coins, dollars, emeralds, etc. There are a lot of different economy plugins with different strengths and weaknesses. Some are simple and some are complicated. One very common economy is Essentials that provides basic money functionality. Unfortunately, very few economy plugins support the ability to keep money separate in different worlds. Essentials does not. Miconomy on the other hand does. If you are an admin and think that you want to allow players to sell items in different worlds, then download and use Miconomy or similar. If on the other hand you only plan to allow players to buy items, then this MultiWorldMoney plugin will work fine.

Vault

The Vault Plugin is a helper plugin that provides a unified interface for other plugins to talk to any economy that Vault supports without having to know what economy is installed. It provides a generic set of functions to call that include multi-world commands, but if the underlying economy does not support multi-worlds then they don't do anything. MWM uses and requires Vault. Make sure you download the latest version.

MWM is not an Economy

MultiWorldMoney (MWM) is not an economy. It's an add-on to any single-world economy to make it multi-world. It uses Vault to interface with the underlying economy plugin, for example, Essentials and tracks what money each player has in each world. When a player moves from one world to another, it banks the money in the old world and replaces the player's balance with what they have in the new world. It also offers a balance command that tells players the sum total of all their wealth in every world.