Money is one of the tools of exchange - not of control.
In capitalism (which means - truly free-market) there's no deal, no exchange until both sides of that deal are satisfied from it.
Those who have more money can have more "power" than others, but it only can (not must) lead to use of physical coercion.
Coercion doesn't need money - man can be phisicaly beaten even by the poorest of the poor.