An organ marketplace doesn't uphold principles of equality because those with more money can buy organs more quickly. Money talks in our society, and someone with more money can outbid another person for organs in such a marketplace. Plus, a black market for organs will exist due to the moneymaking potential of such enterprises.
It is appalling that this question is even up for answering. Just a little while ago, humans were willing to donate their organs to those in need of a organ to survive. If a marketplace is established, what stops people from killing others to secure a high priced organ? Not to mention, it would not be fair for those that cannot afford to buy and organ; they would go to the highest bidder.
IF there was an open organ marketplace, then only the people who could afford a lot of money would have access to organs for transplants. This creates a completely unfair situation between the poorer segments of society and the richer. Just because you have more money doesn't mean you have more of a right to live.
Creating a market place for human organs will not uphold principles of equality simply based on the rules of supply and demand. Human organs are not easy to come by and if there was a market place for them, the supply would be very low. Therefore, the demand would be very high, and those that could afford to buy would get the organs. This by far, is not equal.
An organ marketplace will not uphold principles of equality. The sell of organs should not be allowed to profit from the loss of a human life. Organ transplant is necessary but it should be done freely and with the consent of everyone that is involved. Anything allowing the profiting of this act is just morally wrong.
If the government were paying for organ donations then it would be equal, the person would have an incentive to donate and it wouldn't give the rich an unfair advantage. The government already pays people to donate blood plasma so why not organs? We could save many lives this way.
If human organs were put up for sale instead of on a waiting list, the wealthy people needing organ transplants would simply out bid or out purchase less affluent people. This would not at all uphold the principles of equality that are inherent in the current organ transplant system. This would lead to organ transplant for profit instead of for saving lives.
There would be no way to regulate a marketplace in organs to ensure that there was no coercion, criminality or other impropriety in securing organs for transplant. We have already heard anecdotal evidence of people kidnapped or coerced into giving up organs. Making such a marketplace official would simply increase the incidence of such crimes. It would also introduce an element of corruption into the medical process of determining who is next to get available organs.