Yes, the word 'might' is important which is why I chose it. I don't say that it definitely will emerge. But the surrogate mother case provides a good example, I think. As I guy, I'm running a risk commenting on this because obviously I don't speak from experience, but it seems like there is a fair market price in this case. Surrogate mothers arguably make more than they would in a year at a median-paying job. It doesn't prima facie look like a case of exploitation, but I'm open to being corrected.
Speaking of side-stepping, you kind of talked around the concrete argument and examples I gave. You talk a lot about the generalities of markets and slippery slope-type arguments about where such thinking might lead, but you don't respond in any detail, as far as I can tell, to this specific case or how legalizing the sale of kidneys -- with the appropriate regulatory oversight of course -- leads to the deliterious consquences you envision.
I agree with you, however, that economics is not morally value-neutral. I stated up front that we have intuitions about what it's not okay to do for money. My question is simply why does selling a kidney fall under this heading whereas other examples of 'selling one's body' arguably do not? Your answer seems to be that introducing market forces will make the exchange value-neutral. But isn't that just conceding the point to your capitalist interlocutors? Why not talk about the ethics of markets across the board? The kidney case, then, becomes just one more example, albeit a difficult one, of how we assign value, both moral and economic.

格鲁，谢谢你的链接。我以前可能听过那一集，但有机会我就会记起来。
With respect to Richard's comment, it probably warrants more by way of response than I gave it the first time around. In retrospect, my response seems a bit terse. I was writing in a hurry, but I wouldn't want that to be mistaken for dismissiveness on my part.
显然，我还没有把我的初步建议的具体安排好。那不是这篇文章的目的。我只是想搅局。当然，如果“卖给出价最高的人”是唯一的选择，这个提议就会有问题。但将肾脏出售给出价最高的人——我认为这是最不可取的安排，而且最有可能被滥用——并不是肾脏出售和分配的唯一方式。如果政府器官银行设定市场价格，只在稀缺的情况下才鼓励出售，会怎么样?再说一遍，我只是提出一些想法。
我对把人看成商品的担忧也很敏感。大多数道德敏感的人都有这样的直觉:把人仅仅视为商品或达到目的的手段是错误的。但我不完全确定这一原则在这里如何适用。“出卖身体”的行为本身是否在某种程度上贬低了这个人?所有情况都是这样吗?具体在这个案例中?如果一个人如此自主地做这件事，是否仍然如此有辱人格以至于国家有压倒一切的利益来阻止它?这些都是与这个问题相关的问题。在我看来，这就变成了一种练习，就像随意画线一样。我们在其他地方所依赖的一般原则在这些情况下有用吗?
Also, are there cases in which compensation can actually affirm personhood? Whether we like it or not, the way our society assigns value is through money. Perhaps I'm sensitive to this because over the past five years I gave a lot of myself to a job for which I wasn't fairly compensated. This has a profound effect on one's sense of value and can rightly be described (I think) as a denigration of one's personhood. I don't know if this principle applies here, but there's a fine line between volunteerism that's noble and volunteerism that exploitative. I can envision scenarios in which 'giving out of the goodness of one's heart' or out of a perceived sense of obligation, are more exploitative than setting up mechanisms of fair compensation. Again, whether this applies in the kidney case is debatable.
P.S. I hope that, ultimately, this will be a moot issue, as medicine advances and we can clone replacement parts in the lab. But, still, the process would likely be expensive and may still cost the recepient some money. Would this be less morally objectionable, however?

我想我很好奇是什么让代孕案例和你的肾脏案例不同?为什么女人的子宫是市场的合法领域，而不是某人的肾脏?
I think we might also be in danger of talking about "something called 'the market'" in too abstract a way. Markets can be very complicated entities, but the basis for markets is relatively simple: property rights plus contracts. We generally think this is fine when the arrangement is voluntary and we generally acknowledge that individuals have a high degree of sovereignty over their own bodies. Again, people already sell blood, sperm, eggs, wombs, etc. This at least sets the stage for extending markets to cover kidneys.
The only real issue that I can see -- and I think that this *is* central to both Sandel's and Satz' position -- is the problem of weak agency. In other words, are the persons giving up their kidneys doing so in an informed, voluntary way and not being coerced by some external agency or circumstance. I acknowledged in the original post that these are practical worries. But there are at least two responses available: 1) these worries may be overcome by regulatory oversight (we shouldn't generalize from black markets to regulated markets); 2) the problem of weak agency applies also to donation (as opposed to sale).
But these are all arguments on the individual autonomy side. You rightly bring up the issue of our collective concerns. Well, how about the argument that allowing a market in kidneys would increase supply and reduce the suffering and death of 75,000 Americans on waiting lists? This is a social welfare argument and I think it ought to give us pause. We can talk idealistically about some things being too precious to be reduced to market forces, but in the meantime there are a lot of concrete cases of suffering that go unanswered. It's an exercise in utilitarian calculus, I know, but it speaks to the 'greater good' aspect of the argument.
In any case, it's good to bear in mind the bigger picture, because our moral intuitions may lead us astray. The idea of using someone, even if they are fairly compensated, for spare parts rightly causes a twinge of conscience. However, we typically don't feel that same twinge of conscience in the case of the tens of thousands per year who die awaiting a transplant. This is the problem of silent suffering and it looks suspicously like a cognitive bias in our moral reasoning.
At the end of the day, I suspect that one's position on this issue comes down to how much weight they place on individual autonomy and how much weight they place on the aggregate suffering of those on wait lists. Clearly, kidney markets aren't ideal and aren't without their problematic moral consequences, but we're seldom given the luxury of choosing between ideals. The pragmatic question, then, is "are kidney markets better (or at least no worse) than the alternative?" Tentatively, I still find myself saying 'yes.'