For over 30 years the joint venture between Norm Ornstein of the American Enterprise Institute and Tom Mann of The Brookings Institution has provided a 'Vital Statistics' report on congressional fundraising.
This comprehensive look at congress covers 8 chapters. The study spans a wide breadth of topics from polarization to the decline in legislative productivity.
According to data compiled by Michael J. Malbin of the campaign finance institute, the average cost of a congressional seat has increased significantly. In 2002 the average Senate seat cost $4,758,737 to win election. That has grown to $10,351,556 in 2012. Similarly the an average House of Representatives seat cost $1,163,499 in 2002. Last election, an average representative needed to raise $1,596,953 to win a House seat.