A number of the supporters of the Iraq War suggested that the effort would pay for itself. For a long list of quotations, with citations, go here
Looks like they were right, though not in the way they intended (emphasis added):
The Iraq insurgency has become financially self-sustaining, raising tens of millions of dollars a year from oil smuggling, kidnapping, counterfeiting, corrupt charities and other crimes, The New York Times reported in Sunday editions.
According to a classified United States government report, a copy of which was obtained by the newspaper, groups responsible for many of the insurgent and terrorist attacks are raising an estimated $70 million to $200 million a year from illegal activities.