The normal cost of mailing a letter is bad enough, but a 15-cent stamp may cost you as much as 25 cents these days if you buy it from a vending machine.

And the profit is not going to the Postal Service. The extra money is going to the vendors who own the machines.

The vendors claim that consumers must pay a premium for the convenience of having a stamp when they need it. Profits are split between the vendor and the store-owner.

The Postal Service takes the position that stamps are available at the post office. "It's not our responsibility to offer stamps in every store," an official said.

However, the Postal Service does provide some machines selling stamps at face value in shopping areas, airports and other public places.

Actually, most other vending machine products are marked-up as much as stamps. A candy bar selling for 25 cents probably cost the vendor about 12 cents, and a 35-cent soft drink cost him 22 cents or less.

Vending companies claim the recent postage hike hurt stamp vendors who had to restock their machines and in some cases replace the coin mechanism.

There are at least a dozen manufacturers of stamp vending machines, according to a postal official.Locally, at least two companies - Robeson Vending and Postage Service - handle the machines.

Stamp machines are less profitable, a vendor said, because they must be serviced frequently. An empty stamp machine upsets people more than any other empty vending machine, he said.

If you prefer to pay just 15 cents for a 15-cent stamp, "you're welcome to go to the post office," a vendor said.