 The U.S. Postal Service's 10-year Delivering for America plan is causing the price of stamps to go up again. Starting on July 14th, the price of a Forever stamp will cost 73 cents. It's up from the 68 cents it started charging earlier this year and the 64 cents it cost to send Christmas cards last December. Metered rates will go from 64 cents to 69 cents. Postcard stamps will cost 56 cents.