Here's an excerpt from the executive summary of a new report released by the Center for Strategic and Budgetary Assessments, entitled "Cost of the Wars in Iraq and Afghanistan,and Other Military Operations Through 2008 and Beyond."
Since 2001, the US government and the American taxpayer have provided about $904 billion . . . for military operations, including $66 billion to cover war-related costs for the first part of 2009. Moreover, the wars in Iraq and Afghanistan appear to be far from over. A set of illustrative scenarios developed by the Congressional Budget Office (CBO) suggest that the direct budgetary costs of these military operations could amount to an additional $416–817 billion through 2018—assuming the number of US troops involved in the two conflicts is reduced from today’s level of about 200,000 to some 30,000–75,000 over the next several years. This would bring the direct budgetary costs of these wars to a total of some $1.3–1.7 trillion.
Scroll through the document below, or download the PDF file here: R.20081215.Cost_of_the_Wars_i.pdf