In November 2013, United States House of Representatives member Trey Radel plead guilty to buying cocaine from an undercover officer. According to court documents, the Congressman paid $260 for 3.5 grams of cocaine, which is commonly known as an eight ball, or 1/8th of an ounce.
The actual drug buy took place on October 28, 2013 in Washington DC.
According to figures reported to the United Nations, a gram of cocaine sells for between $8 to $300 in the United States.
(See world cocaine prices here.)
Source: Athena Jones and Evan Perez, “Rep. Trey Radel to take leave of absence, enter drug treatment,” CNN, November 20, 2013.