Some of the issues were touched on in a forum topic about this issue in 2008. Here is a post made then. It contains a link to a British Medical Journal article, which you can read in full by registering on their site:-
This question has cropped up before, here - where the question was whether a prisoner should be allowed to trade an organ for remission of his sentence, and here where the discussion was about a commercial market in human kidneys.
The current issue of the British Medical Journal revisits the debate.http://www.bmj.com/content/336/7657/1342.short
Arthur J Matas, professor of surgery at University of Minnesota, thinks that living donors should be paid for organs such as kidneys. He points out that there is already a clandestine, unregulated trade notably in developing countries, and that it would be preferable to bring this under strict legal regulation, so as to ensure quality of donated organs, to reduce the likelihood of donors being coerced into parting with organs and, hopefully, to increase supply.
Jeremy Chapman, professer in the Centre for Transplant and Renal Research, University of Sydney, is strongly against the idea. He reports that:
Selling organs does not help people lift themselves from destitution. In the bazaars of India and Pakistan, people sell kidneys to pay off debts, but average family income declines by a third, more live below the poverty line, and 86% report deterioration in their health. The only people who clearly benefit are the intermediaries who take money as the kidney transits from the vendor to the recipient: organ brokers, transplant surgeons, hospitals, government officials, and the wealthy health insurance companies of the West and the Middle East.
He also adds that organ sales destroy donation. Nobody will donate a kidney to a family member or friend if government provides a supply by purchasing from organ vendors:
Which recipient will risk a family member’s health when government will pay? And if a kidney is worth money before death, families or individuals will demand money for consent to retrieval of organs after death. Surely the payment must be higher after death because you can use organs that cannot be retrieved from live people?
The consequences of regulated organ purchase will be an implosion in organ donation, reduction in kidney transplantations and destruction of heart, lung, liver, and pancreas transplantation. Purchase of organs is not the answer.
Medical factors involved in organ transplants are well understood. What is in dispute here is the economics and ethics of it.