Joseph Stiglitz, a Nobel Prize-winning economist and self-described opponent of the war, puts the final figure at a staggering $1 trillion to $2 trillion, including $500 billion for the war and occupation and up to $300 billion in future health care costs for wounded troops. Additional costs include a negative impact from the rising cost of oil and added interest on the national debt.
A little math from a Metafilter poster puts things in perspective:
To get a grip on it, observe that the CIA says the average annual purchasing power of Iraqi citizens is $3,400, and there are about 7,500,000 males between 15-65 years old in Iraq. Divide this out, and it turns out that by the time we’re “done” with Iraq, we could have hired each and every man in Iraq and paid them their average annual income for 39 years.