Jeri's usually accurate... or at least occasionally. On second thought, I think RUS probably has it right.

The second one makes sense (prisonerS), if the singer were addressing more than one person.

And freedom, o freedom, that's just some people talkin'
You're prison is walking thru this world all alone

Paraphrase department: The 'freedom' of the open road is a myth. Freedom needs love, and being alone in this world is the same as a prison for YOU.