WASHINGTON – Diamonds are forever, sure. But postal rates?

Coming soon to your neighborhood post office: a stamp that can be used eternally, even if rates are increased a dozen or more times.

The Postal Regulatory Commission recommended Monday a new way of buying stamps – locking in a rate to mail a first-class letter in much the same way home buyers snag a good rate on a 30-year mortgage.

Under the plan, the first “forever stamp” would cost 41 cents. That is because the commission also proposed increasing the first-class postal rate by 2 cents. The independent commission trumpeted the hike as a victory for consumers because the Postal Service had wanted a 3-cent jump.

But the cost of mailing most packages, magazines and postcards would also rise under the commission’s recommendations, which must be approved by the Postal Service’s Board of Governors to take effect.

The board generally follows the commission’s recommendations. The last time the board deviated from a commission recommendation on the price of a first-class stamp, for instance, was in 1980, Postal Service spokesman Mark Saunders said.

The board is expected to act early next month, and the Postal Service plans to hold a news conference this spring to unveil the image of the forever stamp, Saunders said.

The stamp could be available as early as May, when the postal-rate hikes also would take effect.

“You say nothing lasts forever, but this stamp will,” Saunders said of the forever concept, which some foreign postal administrations, including Britain’s and France’s, have embraced.

“When your great-great-great grandchildren go through your junk drawer at home, when they are excavating your house, they’ll say, ‘What are these?’ – and they’ll still be able to use them.”

The stamp will be a boon to customers because it will save them trips to the post office every time rates go up, said Steve Sharfman, the commission’s general counsel.

“Post offices often run out of stamps after a rate increase, and that’s also frustrating to customers, especially after they’ve been standing in a long line,” he said. “This is a win for the Postal Service, too, because clerks won’t have to spend as much time selling stamps.”

A forever stamp would not carry a denomination, and it would be sold at the going rate to mail a first-class letter.

But the commission recommended that a limit be placed on how many of these stamps can be sold to any individual or organization at one time. The limit has not been set, but Sharfman observed, “If someone comes in and wants to buy $1 million worth of forever stamps, that’s not reasonable.”

The commission announced its recommendations today after hearing testimony in recent months from 99 witnesses, many of whom weighed in on why rates should – or should not – be changed.

Last May, the Postal Service announced that it needed to increase the rate of a first-class stamp to 42 cents or face the prospect of operating in the red. But the commission found errors in the Postal Service’s budgetary calculations, Sharfman said.

“This is not a story about a big confrontation between us and the Postal Service,” he said. “They just didn’t need as much of a rate increase as they thought they did.”