I have FIRST CLASS mailing stamps which say USA FOREVER 2011, Do they expire?
It shouldn't. USA forever means you don't have to pay more if the price of a stamp changes if you mail it. You can use it any time you want and it won't expire.
No they do not hence the name forever.
No. A forever stamp guarantees it will always be a 1st class stamp, no matter what it costs at time of purchase.
I don't think that your stamps will expire if they are "Forever Stamps", but I would ask the postal worker at the post office to be sure.
Forever stamps never expire, and if the cost of a first class stamp goes up, the value of a forever stamp rises. For example, the bell stamps purchased at 44 cents each are now worth 45 cents each.