Most of the recipient countries cannot afford brand-new equipment on their own; the Philippines, Morocco and the Dominican Republican have been recent shoppers. But first-world countries like Australia and Canada have picked up some cheap castoffs, as well.

There is no central site where all the weaponry is gathered for inspection by would-be buyers. Instead the merchandise is offered on an “as is, where is” basis, with the buyer having to pay for shipping and repairs — which can sometimes make the bargain less appealing and accounts for why not all the merchandise moves. Few shoppers, however, complain — and they often observe the hand-off of weapons in ceremonies in their home countries, with American officials in attendance.

“We’re grateful,” said Sgt. Maj. Irving Estrada, assistant to the military attaché of Guatemala. His country has received used body armor, flight suits, boots and computers which were presented by the American ambassador at a ceremony in Guatemala City last April.

“This is very important to us,” said Sergeant Major Estrada. “Everything is useful and we use everything that we get.”

The program is not without its critics, who say it contributes to a global arms race and may be a short-sighted way of winning friends.

“Aren’t there more constructive ways for the United States to make friends?” asked Danielle Brian, executive director of the Project on Government Oversight, a watchdog group that studies Pentagon spending. “We are arming countries that otherwise would not afford to be armed. If we want to make friends, we should have something better to offer.”

Critics also say the tag sale are giveaway metaphors are not apt, and prefer to describe it in terms of a business giving out free samples. The program, they say, gives nations a taste of weapons that they might like to purchase later, often with foreign aid from the United States.