Financial aid to Pakistan since 9/11 From U.S.
Between 2002-2010, Pakistan received approximately 18 billion in military and economic aid from the United States. In February 2010, the Obama administration requested an additional 3 billion in aid, for a total of 20.7 billion.
Western officials have claimed nearly 70% ( roughly $3.4 billion) of the aid given to the Pakistani military has been misspent in 2002-2007.
The official foreign aid is just part of it. A chunk of the money we spend on the Afghan War also goes into the Pakistani economy, as all supplies need to pass thru Pakistan. We probably also pay Pakistanis for supplies, construction work, etc.