Depending on who you ask, the Iraq war costs anything from a low $200 million [1], to a moderate $411 million [2] to a whopping $720 million a day [3].
The American Friends Service Committee [4] calls for the immediate withdrawal of U.S. troops from Iraq and they have put together this video describing in numbers the financial toll the war is having on the country's ability to deal with its domestic issues. When you spend $720 million [5] in a failed war, you can't spend it in health care, schools, jobs or the current housing crisis.