A first-class stamp in the United States costs 49 cents as of July 2014, according to the U.S. Postal Service. A stamp marked "Forever" is always the first-class postage rate, no matter when the stamp was purchased. Bulk mail rates are cheaper.
The first-class rate rose to 49 cents on Jan. 26, 2014. The rate was 46 cents in 2013. The price for a single first-class stamp was above 40 cents since May 14, 2007. First-class mail delivery started in 1863 with 3 cents for a half-ounce of mail. The postal rate in the United States rose to 10 cents for first-class letters in March 1974.