It’s an undeniable fact of life that nothing lasts forever. Well, except maybe that stamp you bought last week.

With U.S. Postal Service rates set to increase Monday, some consumers are locking in a good buy with the Forever Stamp.

Introduced in April 2007, the Forever Stamp is a First-Class postage stamp that will remain valid regardless of any future postage rate increases. While its retail price will always be the current postage rate for a one-ounce, First-Class letter, the Forever Stamp never expires or needs additional penny stamps when the postage rates go up.

“The Postal Service developed the Forever Stamp for consumers to ease the transition during price changes,” Postmaster General John Potter said. “We encourage Americans to buy Forever Stamps now for 41 cents, because like the name suggests, they are good forever.”

After announcing in February postage would increase to 42 cents May 12, the U.S Postal Service has reported a boom in Forever Stamp sales, as customers have been buying the stamp at a rate of about 30 million per day. That totals more than 6 billion sold since its introduction.

The Litchfield Post Office is also seeing demand rise. Postmaster Steven Hendrickson said during the last week of April, the Litchfield office sold about 300 books of 20 Forever Stamps per day. On May 1, the office sold more than 500 books.

“Yeah, we’ve been selling a lot of them,” he said. “People know the next increase is coming; they know of Forever Stamps; and obviously it’s a good buy.”

Unlike regular stamps, the Forever Stamp, which features the U.S. Liberty Bell, does not have any money-value printed on it. It simply says, “USA First-Class Forever.” Because of this, it can be used beyond the May 12 increase without the need for a 1-cent stamp.

Read more in the May 8 Independent Review.