It feels like you are playing the "Gotcha!" game with the goal of winning rather than communicating your objection to organ selling. I can't see why else you would argue that organ donation is regulated sale with a price $0.
In that case I am not likely to respond further. It seems obvious to me what the benefits are of a high price with thorough testing, informed consent and exclusion criteria : it would solve the organ shortage and allow for faster advances in research. As to what the harms are I am still unclear.
It's not a gotcha. I'm not just saying "well, technically, $0 is a number, so that fits what you literally said". Limiting the price to $0 really is regulation of the price; setting the price to $0 is meant to alleviate some of the problems that could result from allowing a higher price, because it changes the incentives.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.