Mailing a letter will cost you just a little bit less starting this past weekend. The U.S. Postal Service announced Thursday that a first-class stamp for a 1-ounce letter will cost two cents less, down to 47 cents, beginning Sunday. Postcard stamps also are 1 cent cheaper, at 34 cents, while ... » Learn More about Price of Mailing a Letter Dropping to 47 Cents Starting Recently