Nothing lasts forever — not even 50-cent postage stamps.

The U.S. Postal Service announced that the cost of its Forever stamps will rise 5 cents apiece on Jan. 27 to 55 cents.

The 10 percent spike is the largest price leap since 1991.

Each additional letter ounce will cost an extra 15 cents, which is a decrease from 21 cents. The cost to mail a 2-ounce stamped letter will actually drop from 71 cents to 70 cents, and the cost of a postcard will remain fixed at 35 cents.

Priority mail will also rise about 10 percent. A priority small box that once was $7.20 will rise 70 cents, and a priority medium box which previously cost $13.65 will now set you back $14.35.

In 2018, the Postal Service lost about $3.9 billion — more than $1 billion more than the previous year. For 12 straight years it has been hemorrhaging cash, and it is not taxpayer-funded. It generates revenue from selling products and services.

The price hikes come amid criticism from President Donald Trump, who referred to the USPS as Amazon’s delivery boy, falsely claiming the online commerce behemoth has cost American taxpayers billions of dollars.

“Why is the United States Post Office, which is losing many billions of dollars a year, while charging Amazon and others so little to deliver their packages, making Amazon richer and the Post Office dumber and poorer?” tweeted Trump in late 2017. “Should be charging MUCH MORE!”