A true free market?

(Sorry to butt in, Neb)

Is there an example of anarchy that is not specially disqualified from being evidence against that particular system?

Anarchists, I feel, are the type of people who say that by definition anarchy must work. When it doesn't, it's not "true" anarchy. I've had to beat this problem out of a self-confessed anarchist before, he's almost about to grow out of it.