Green’s Dictionary of Slang

(US prison) the free world, i.e. the world outside prison.

1967		C. Cooper Jr Farm 221: Maybe not for you. Maybe you had somethin goin with her in the Free, and I didn’t know about it.
1974		Andrews & Dickens Over the Wall 11: We would like to extend heartfelt thanks to those solid-gold folks out there in the free.