I remember the story fairly well; I've just forgotten the title. (And the author.) I have the impression that the story goes way, way back to the 1950s, but that may be inaccurate. I first read it in an old paperback copy of a science fiction anthology which I picked up around the late 1980s. English language, and I believe the story I'm looking for was short enough to qualify as a short story, rather than a novella.
The first-person narrator doesn't actually do much in this tale; he's more of an observer than an instigator. I believe he had a background in journalism, and I think he was working for the White House when the story began. (Could be wrong on that last part.) At any rate, he describes the peaceful arrival of a couple of alien emissaries who said they wanted to befriend us, and even share some of their advanced technology with us. Free of charge, I believe. (At first.)
I don't believe the aliens looked perfectly human, but I have a vague impression that they were basically shaped the same as us -- two arms, two legs, one head atop the torso. They showed off some of their technology and gave interviews and so forth. They had learned to speak fluent English (and possibly other human languages), and seemed quite charming.
The turning point in our relations with the aliens came when those two emissaries were being interviewed on a TV show. The host asked a question about conditions on their home planet -- probably something about average life expectancy, or how they treated cancer, or something along similar lines -- and the aliens said their species never had to worry about all that stuff nowadays. Why not? Because of some sort of super-duper automated cure-all stations which were located in every major city. Go in there from time to time, and it would cure your current health problems. (Physical health, that is -- I don't recall mental illness being mentioned.) I'm not sure if it also made an old person into an unwrinkled and energetic young adult again, but it may have. Anyway, the host was stunned, but asked why they'd never mentioned this medical miracle before, and the aliens said virtuously: "You didn't ask."
Millions of people saw that broadcast at the time, and immediately wanted to know when they were going to get the benefits of that particular bit of technology. So the U.S. government (and others) quickly saw that now it was time for some serious bargaining. The aliens, when approached by human political leaders about the possibility of obtaining such technology, made it clear that those cure-all stations did not come cheap, unlike some of the other trinkets which the aliens had been sharing. The alien civilization had no use for our paper money, nor for large masses of silver and gold and other conventional "precious metals," but they could find use for radioactive minerals such as uranium ore. All of it. (Not just the stuff that had already been mined out of the ground so it could be used to make atomic weapons or other high-tech contraptions.)
I think the narrator says that he personally participated in some mining activities over in Africa in order to extract from the ground the last traces of some uranium deposits in that region. The same sort of thing was simultaneously happening in several other parts of the globe. After months of labor, it appears that everything that was reasonably accessible to our modern mining technology had been gathered together in one place. (No suggestion that the aliens intended to make us go miles beneath the surface of the earth, nor start mining the ocean floor, for that matter -- there might be more uranium down there somewhere, but the aliens preferred to take what was readily available.) So the aliens handed over those cure-all stations, which were distributed to every major city and performed exactly as advertised, and then the aliens flew off in their ship with all the radioactive minerals.
The narrator had a friend who was supposed to be a brilliant young scientist. The friend had previously complained about a) not being able to make sense of some of the samples of alien technology which had been handed out, and b) not being allowed to crack open one of these cure-all stations to see if he could reverse-engineer the principles which made it work. The friend finally got his wish, though -- a month or two after the alien emissaries had left our solar system, the cure-all stations stopped functioning. Then the friend was part of an elite team permitted to open up the machinery and figure out what had been going on and why it wasn't happening any more.
The scientific team found faint traces of uranium and/or other radioactive minerals . . . and suddenly realized that the entire human race had just been swindled on a colossal scale! It must have been that the alien cure-all stations were running out of fuel, and so they decided to go convince some backwoods yokels (Homo Sapiens) to give them a fresh supply so that they could continue to heal and rejuvenate their own population for many, many years to come. Meanwhile, the humans would have no way to refuel their own cure-all stations, which were basically "running on fumes" when delivered to us. The aliens were probably laughing all the way home!
But in the last few lines, the narrator makes it clear that the humans intend to get the last laugh after all. Certain lines of scientific research became Absolute Top Priority as a matter of political necessity (i.e., any political leaders who refused to get on board with funding this research program would have been lynched), and within a few years, a brilliant breakthrough had been made in how to synthesize radioactive minerals from scratch! Once mass production was achieved, the cure-all stations could be brought back online, and there'd still be plenty of radioactive material left over for powering and arming a huge fleet of warships which was going to fly off to the alien homeworld and arrive with blood in its collective eye. (I think the plan was to make a show of force, and then give the aliens a chance to surrender unconditionally if they knew what was good for 'em. But I may be wrong, or it may have been left unclear.)
So now I just want someone to refresh my memory of the story's title, and more importantly who wrote it. It may be someone whose other work I am already very familiar with -- but if not, I'd like to check out some of his (or her) other published stories, if any.
I spent some time Googling, and kept finding references to stories which I am sure are not the same one I just outlined. For instance, this particular story about aliens pulling a fast one on us naive humans is not any of the following:
The Greks Bring Gifts, by Murray Leinster.
"To Serve Man," by Damon Knight.
Any of the stories reprinted in The Trouble With Aliens, a collection of short fiction by Christopher Anvil. (And probably not any other short story by Anvil, either; I've read many but not all of his published works within the last several years.)