It might be called a "Forever" stamp, but not when it comes to the price of buying one.

The cost of mailing a one-ounce first-class letter will return to being 49 cents, up from 47 cents, where it had been since April.

The last increase came in January 2014, according to the U.S. Postal Service, when it went from 47 cents to 49 cents. Then last April, the Postal Regulatory Commission ordered the USPS to drop its prices for the first time in 97 years. Postmaster General Megan Brennan protested, saying, "given our precarious financial condition and ongoing business needs, the price reduction required by the PRC exacerbates our losses."

So now the price is going to back up again. Postcards, letters mailed to other countries and heavier letters aren't affected.

The word "Forever" refers to when it can be stuck on an envelope and get the letter to its destination, not how long its cost will remain unchanged.

"Once it’s purchased, it never expires or declines in value, but at the time of purchase, it’s sold at the first-class one-ounce rate. You can use it forever," said Elizabeth Najduch, the USPS spokeswoman in Detroit.

Forever stamps were first introduced in April 2007, and within four years, all first-class one-ounce stamps became Forever stamps, except those sold in coils of 500, 3,000 and 10,000, according to the USPS website. They were developed "for consumers ease of use" during price changes.

"The idea was never to deceive anyone or anything of that nature," R. Richard Geddes, an associate professor of policy analysis and management at Cornell University and an expert of the Postal Service, said about the name of the stamp. "It used to be if there was a change in postage and you had old stamps, you put them on with a two-cent stamp or a one-cent stamp. The idea was buy their group of stamps right now and that price will hold for the foreseeable future, so you wouldn't have to put on those one- or two-cent stamp additions."

According to Geddes, the USPS needs to periodically adjust the price of postage to compensate for even modest levels of inflation, as its own costs — gas for mail trucks, wages, heating and lighting its buildings — go up.

But Lynne Golodner, the chief creative officer of the public relations firm Your People of Huntington Woods, Mich., was annoyed by the cost hike. She buys stamps in bulk.

"I was stunned. It feels like we just had another increase," she said. "It’s an inconvenience, I am kind of old-fashioned. I use stamps, I pay bills by mail. I mail out checks to employees. I guess I could a lot of that digitally, but I just don’t."

The Forever stamp had previously cost 49 cents, but the Postal Regulatory Commission ordered the USPS to drop its prices in April, the first time in 97 years.

At the time, Postmaster General and CEO Megan J. Brennan expressed concern: "Given our precarious financial condition and ongoing business needs, the price reduction required by the PRC exacerbates our losses."

The USPS processed and delivered 154.2 billion pieces of mail in 2015, according to its most recent data.

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