What's the cost of war? Obviously there's so many ways to measure it in terms of the devastation it wreaks on untold numbers of lives. But, let's be more crass here: show me the money. The National Priorities Project shows its version of the Cost of War:
Currently, the War in Iraq has cost $341,390,328,877.
Instead, we could have hired 5,916,339 additional public school teachers for one year.
Instead, we could have provided 16,549,869 students four-year scholarships at public universities.
Obviously there's moral, theological and other important issues involved here. But seriously, those numbers are appalling. The site above also has a way to see the impact of the war on local communities in terms of pure $. For instance, the war has cost Fargo, ND (population: 90,672) $59,636,965. This is ridiculous, even from a purely economic point of view.

Go check out the Cost of War site. It has a counter of the Cost of War, and it's now up to $341,392,190,394.