Dill's lack of any real stable home life makes him a "free man." Because he is shipped around to different relatives at different times of the year, he is an exception to the average child in the nuclear family model of the 1930s: Mom, Dad, and kids all living under one roof. Scout and Jem are also being brought up in a non-traditional home at this time, but their existence is one that is both structured and stable, unlike Dill Harris's life of chaos, turmoil, and constant transition. While Dill would like for people to believe that he sees himself as a "free man," in all truth he would like nothing better than to be in a reliable and comfortable home like the Finches'.
Dill certainly frees himself up when he runs away from Meridian in Chapter 14. After thinking she had stepped on a snake at night in her bedroom, Scout discovered it was only Dill hiding under the bed. He had ridden the train to Maycomb Junction and then walked the rest of the way to the Finch house after having another falling out with his "new father," who bound him in chains and left him "to die in the basement." His freedom lasted only a short while, since Atticus notified his Aunt Rachel who then contacted his parents. But he got to snuggle with Scout in bed that night and was allowed to stay in Maycomb for the big trial. Although Aunt Rachel kept an eye on him (when she wasn't drinking her morning constitutional), he had a great deal of freedom far from his home and the parents whe farmed him out each summer.
Dill is a boy who comes from a home that has poor family dynamics. Because both of his parents fight over him and his mother is with different jobs and boy friends, he moves around a bit.
One of the ways he is a free boy is that he is able to go to the movies regularly when he is at his home city.
I can not really see Dill as a free man. He is cared for by elderly relatives and later they send him off to military school which he refers to as his different prisons.