The average cost of winning a campaign for a seat in the U.S. Senate in 2012 was $11,474,362
The men and women elected to Congress, fund their elections with other people's money. The donors are primarily corporations which provide the means for the candidates to get elected. Once they are elected they repay their benefactors by passing the legislation that benefits their donors. Congressmen and women do not represent the people who elect them, they represent the corporations who fund their election.