So you can't be a wizard without coins, but you need to be a wizard to MAKE the coins... there's a circular loop here that needs a start.

Once you are a wizard, you then need to monopolise the world market on 'special coins', so it is worth going on elaborate assassinations to steal other people's pile of coins. And once Insert Bad Guy Here gains such a stockpile that it cannot be effectively matched by any one person or any group of people... they get to kill everyone who has coins, become super powerful and take over the world.

Just a thought...