Stamp price jumps to 49 cents on Monday The U.S. Postal Service will increase the cost of a stamp on Monday to 49 cents from the current 46 cents. The spike is a 6.5 percent jump, contrary to the Postal Accountability and Enhancement Act, which states that stamp prices cannot increase faster than the rate of inflation, The Wall Street Journal reported. Mounting financial losses forced the USPS to ask regulators to authorize an increase greater than the rate of inflation, which the agency was granted. But regulators refused to make it permanent, a move that upset Postal Service officials, according to the paper. The 49 cent stamp price is guaranteed for two years.