It seems to me that a "free market" is an oxymoron.
Either a society can create a market which tends towards being free as an end, or a society can create a free market in terms of the means by which people trade.
One textbook definition of a free market is one where there are no barriers to entry. Where all information flows freely and everyone has access to good information and can start competing businesses with no hurdles besides the pure business-related problems of acquiring capital, labor, etc.
Another definition of a free market is that all possible transactions should be allowed without hindrance. This would include contracts that force people to limit information disclosure, contracts that limit who can sell what and at what times, contracts that force you to also sell X if you want to sell Y, etc.
Now in the first definition I shouldn't be allowed to pay to have information hidden or pay to create a barrier to trade. However, under the second definition I should be able to engage in a transaction which limits the flow of information or makes it more difficult for someone to compete against me.
So you have some people who support free markets who believe in antitrust law because in the long run monopolies tend to stifle competition. On the other hand you have people who support free markets that think antitrust law is the worst possible form of legislation. They believe that you should allow monopolies to do whatever they will. They trust that over time monopolies that spend more money on stifling competition than on improving their own competitiveness will fail.
However, as I look around me I see that there is a huge amount of time and money being spent by lots of people trying to hide information and stifle competition. And all of this done in the name of free markets so long as someone pays to have information hidden (or it is written into a contract) or someone pays to keep somebody else out of a market.
What are your thoughts?