http://marketdesigner.blogspot.com/2009/06/michael-sandel-on-markets-and-morals.html
A lot of markets are "repugnant", that is, many people don't think they should exist. The boundaries of what is viewed as repugnant changes dramatically over time.
My view on this is that markets exist whether you like them to or not. Steve Jobs recently bought himself a liver in the US, even. Markets are everywhere. Life is full of trade-offs and everyone has a price. There is no distinction, to me, between prostitution and someone who quits his/her job once he/she has a baby.
There is no distinction between the economic, the moral, and the political-- economics is not just about money. People pay with their time, their effort, their reputations, etc. "Political capital" and "social capital" are just two manifestations of that idea. Even a hermit in the woods has a market with himself--the marginal value of everything is equal to the marginal value of everything else.
I'm against the legalization of prostitution and the legalization of kidney markets; indeed, I think they're currently massively
under-regulated. Coercion is a huge problem in both of those, and until coercion can be effectively eliminated without too many restrictions on other freedoms (i.e. markets).
Yes, maybe this is a bizarre way to go through life, but I think it's a framework more helpful than not. It obviously can't be
both consistent and complete, but so far I haven't found any contradictions or gaps.