From the Winston-Salem Journal:
House members of the North Carolina congressional delegation spent more than $1 million of taxpayer money on bulk mailings to constituents during the last Congress. Some sent thousands of pieces of mail and others sent none, according to congressional records.
The practice, known as franking, allows members of Congress to send communication to constituents, with the member's signature on the envelope, in place of a stamp.
. . .
According to Public Citizen, a national consumer watch-dog group, the average amount spent by House members is $55,000.