With the Citizens United decision in January of 2010, corporations and other outside interest groups were allowed to spend limitless money on political elections. Outside contributions rose from $69M in 2006 to $304M in 2010. From www.opensecrets.org
In 2011, Nancy Pelosi attended 400 fundraisers [from Planet Money, direct source needed]
In 2008, the cost of winning a federal election was $1.3 million for a House of Representatives seat and $7.5 million for a Senate seat. [from http://www.cfinst.org/data/pdf/VitalStats_t1.pdf]
Total spending on lobbying from 1998-2011, from www.opensecrets.org.