As the medical science and practice are advancing, transplanted organs work better in new bodies, making the need for organs more apparent; however, in economic terminology, supply is way behind the demand curve:
“Organ transplants are one of the extraordinary developments of modern science. They began in 1954 with a kidney transplant performed at Brigham & Women’s hospital in Boston. But the practice only took off in the 1970s with the development of immunosuppressive drugs that could prevent the rejection of transplanted organs. Since then, the number of kidney and other organ transplants has grown rapidly, but not nearly as rapidly as the growth in the number of people with defective organs who need transplants. The result has been longer and longer delays to receive organs.” 
So, where do we get new organs, if there are not sufficiently many people willing to let go? Perhaps, science can help us here: what about growing organs in the lab?
Of course, as usual, fiction (or rather, science-fiction) has already offered several other alternatives, for example, cloning people in order to harvest their organs later on. You can read several science-fiction stories and watch movies with this theme; here two recent ones: Never Let Me Go (2010) and Moon (2009).
This is fiction, of course.
The reality is however is on its way; two economists: “Mr. Becker is a Nobel Prize-winning professor of economics at the University of Chicago and a senior fellow at the Hoover Institution. Mr. Elias is an economics professor at the Universidad del CEMA in Argentina,” offer the following solution: You can sell your organs.
Well, we spoke about suply/demand curve above, so economists feel qualified to chip in. They give analyses and examples on how and why this might work.
Who is “you” above? I could offer one interpretation: You is the one that “needs” the money, obviously, poor people. And, who might possibly “buy”. Well, rich people, of course! Poor selling their kidneys to the rich would be morally acceptable to some, since it is the capitalistic solution.
But what should the rich stop there? As, my friend Mark Gannon puts it “…because the next logical step for capitalism is for the poor basically to be kept around so their organs can be harvested for use by the rich. We all know only those who have money ought to be able to get organs for transplant!?”
Still, I would say Mark’s scenario is much more humane than the following: Sending mercenaries to harvest organs in other countries; armed with guns and scalpels. A new form colonialism, I suppose. Perhaps as the ships carried (almost) live bodies of slaves from Africa to Americas up to the 19th Century, our high-tech, refrigirated airplanes would be flying from all unfortunate places to the Elysium, filled with (almost) live organs.
It seems that while we ascend to other solar systems or perhaps to other galaxies on the wings of science, we also have the capacity to descend even deeper into the moral oblivion.
 Cash for Kidneys: The Case for a Market for Organs. The Wall Street Journal, January 18, 2014.