http://www.brook.edu/views/op-ed/ohanlon/20021009.htm"An invasion to overthrow Saddam Hussein would likely cost the United States about $50 billion, though it could plausibly range from $25 billion to $75 billion or so, with likely annual U.S. costs of maintaining order in Iraq ranging from $5 billion to $20 billion for a number of years thereafter."
"...a war to overthrow Saddam would involve about 250,000 American forces." (Note: We have 150,000 troops there.)
http://www.gulfinvestigations.net/document396.html"Iraq's chemical, biological, and nuclear weapons programs, together with long-range missile development, and alleged support for terrorism are the justifications put forward for military action. Though initial emphasis was on the ouster of Saddam Hussein, the Administration has more recently pointed to weapons of mass destruction (WMD) disarmament as its prime objective."
"In 2002 the Administration considered a range military of operational plans ranging from a so-called "lite" option involving primarily special operations forces and indigenous opposition groups to a "heavy", large-scale invasion option put forward by U.S. Central Command.
The Administration initially rejected the heavy option as depending too heavily on regional cooperation and requiring too long to deploy the necessary forces,
even though it offered the surest possibility of success."
"Though costs remain very difficult to predict, several estimate have been put forward, ranging from $50 billion to $1.2 trillion depending on the factors included (e.g., occupation costs, economic consequences)."
That second link is long and detailed. I think it's wise to remember, especially for any lurking eyes, what this war was supposedly originally about: the idea that Iraq was a threat to us and that Hussein had HUGE stockpiles of WMDs.