Forever stamps are U.S. postage stamps that have no price printed on them.
The value of a Forever Stamp is whatever it costs at the moment to send a letter first class, regardless of when you bought that Forever Stamp.
Thus, a Forever Stamp never declines in value. In fact, it actually increases in value as the cost of postage increases. It's kind of like "rent control for stamps".
Good News & Bad News
The bad news...
There's another postage rate hike around the corner: May 11, 2009!
The Governors of the U.S. Postal Service have approved new prices for mailing services, including a 2-cent increase in the price of a First-Class Mail stamp to 44 cents. Prices for mailing services are reviewed annually and adjusted each May. The new prices will go into effect Monday, May 11. -- Postal News Blog
The good news...
If you already have some Forever Stamps on hand, they will be worth more on May 11th when the newest postage rate hike goes into effect. Yep, the value of a Forever Stamp automatically increases from 42-cents apiece to 44-cents apiece -- the new first-class postage rate.
If you haven't already invested in a good supply of Forever Stamps, you might want to now... before the rate hike takes place!
Customers can continue to mail letters at today’s prices by purchasing the Forever Stamp before May 11. Forever Stamps were developed to help consumers ease the transition during price changes. Forever Stamps do not have a denomination and will be honored whenever they are used with no need for additional postage for a one-ounce letter mailing. On May 11 the price of the Forever Stamp will be 44 cents. -- Postal News Blog
Continue reading: Forever Stamp Pros & Cons
Bartering For Great Deals - The Best Online Barter Exchange Websites