 after breast cancer treatment. Stamps are about to cost more again. Vacation postcards will cost you more, and that forever stamp is going up again. Starting July 14th, 73 cents for a first-class stamp, up 5% in the Postal Service filing for its second price hike this year. Postal just raised the forever price to 68 cents in January and plans to boost international postcards and letters from $1.55 to $1.65.