[sli]

If you feel like being specific, free markets have to exist without government regulation, without monopolies, without economic privilege, and without artificial scarcity, which doesn't really work in the real world under capitalism. Almost no markets are truly free markets, even the ones that look free, because there are general regulations you still have to follow (you can't legally sell poisonous handmade goods at a craft fair, for example -- laws about that act as a regulation).

[tathougies]

Non scarcity is not a requirement for a free market. No artificial scarcity.