ABC Tip: Beat stamp price rises. Next Mon - standard 1st & 2nd class up 2p. The price of a 1st class standard letter rises to 67p, 2nd class to 58p. Large letters rise by 3p to £1.01 (1st class) and to 79p (2nd). As stamps just say 1st or 2nd, if you buy today stamps are valid forever.