If free will was truly non-existent, it would mean that a theoretical entity with access to perfect information would be able to perfectly predict your actions. I don't believe that is possible; I think that human beings are too irrational. Consider a very simple decision: what am I going to have for dinner? You could know the restaurants I have access to, what food is in my home, what I have discussed in a given day, and even what my current mood is, but it can ultimately come down to a whim. I could choose something I've never had before, for no reason, and seek it out.
I believe that we are individual actors in a very complex system that introduces lots of constraints to our decision-making process. We may not even be consciously aware of some of the constraints; however, we are always the ones ultimately making the decisions. You always have the option of a whim.