It may be time to buy some of the Postal Service's Forever stamps.
But the Forever stamps will still be valid for first-class postage after that, and they can be
purchased for 41 cents until the new rates take place.
The post office has sold 5 billion Forever stamps since they were introduced last April.
It plans to have an additional 5 billion in stock to meet the expected demand before the May price change.
Postage rates went up last May, with a first-class stamp jumping 2 cents to the current 41-cent rate.
