According to the U.S. Postal Service, the price of a first-class postage stamp in the United States is 49 cents as of June 2014. This rate applies to standard-sized mail weighing 1 ounce or less. Letters weighing more than 1 ounce cost an additional 21 cents to mail.
Stamps.com states that on Jan. 26, 2014, the rate for first-class postage increased by 3 cents. Rates for other classes of mail also changed. The USPS added a first-class postage rate for metered mail. The metered mail rate is 48 cents per 1-ounce letter. This rate is 1 cent less than mailing a letter using a retail-purchased postage stamp.