since were talking about money..
initially Wolfowitz predicted this war would pay for itself from the rich Iraqi oil revenues.. of course he was totally 'offbase' (to use his own term) in his prediction..

here is what Joseph Stiglitz (the former Chief Economist of the World Bank) has to say about the cost (in a downloadable pdf) click on economic costs of Iraq war

taking into account the macroeconomic costs the conservative estimate ranges from 1 trillion to a moderate estimate of 2.23 trillion..