Not in the UK or the United States. You can use them even when the price has gone up after you bought them, as long as the face value adds up to the correct rate.
{| |- | No, they do not expire. The US hasn't devalued postage since the Civil War. As long as you have the proper total value on the envelope the stamps can be added in. |}
First class postage is 45 centsFirst class postage is 45 cents
Up to 1oz first class postage letter is 98 cents.
current first class postage to the Philippines is
First Class postage is currently 44 cents.
first class postage to Canada is .72 cents.
First Class postage is 45 cents.
The postage for a standard first class letter is 44 cents.
how much is postage for a first class letter from US to Switzerland
First ounce for First Class Postage was .29
45
$1.90
In 1950 until 7/31/58, first class postage was 3 cents.