In 2008, members of Congress were paid $169,300. Periodically stories surface about Congressional Reps sleeping in their offices or taking D.C. housing as a bribe (Minnesota Sen. Norm Coleman most recently). Atrios mentions it here.
So how much extra does it cost to be a Congressperson? They live away from home in D.C. when Congress is in session. They return to their district on weekends to be with their family or visit the district. They need to keep up appearances. Let’s make a list:
D.C. Apartment: $2,500/month
Clothes & dry cleaning: $1,500/month
Weekly flight home: $500/wk x 40
So after accounting for the special expenses that come with the job, a Congressperson makes over $100k a year. Not a gold mine, but by itself almost double what the average family makes. And this is, I think, fairly conservative, as some of these expenses get picked up by campaign funds, and from the stories many Congresspeople have much cheaper D.C. digs, have a shared apartment, etc.