I had many posts on this topic in 2011, collected here. It occurs to me that there is a simpler argument in favor of free will, despite all the current discussion that we are all quite automatic and unmovable in our views.
We can imagine alternative courses of action. We might vary greatly in how objectively we view the alternatives. We might at times only be pretending to consider Actions B or C; we might be weighted far more strongly to a particular course than we are aware. Yet with a very little effort, we can play out the consequences in our minds, and change our minds. We can "think better of it." We can seek advice and modify. It is so obvious in our daily interactions as to be invisible.
But most of all, the mere fact of imagining creates real choice. Even an inconsistency, a randomness, a Dungeons&Dragons die-roll sort of freedom comes in. It might only apply to 1% of our decisions. I think it is a great deal more, but let us look to the minimum, just for argument. Once there are a dozen doors, more than one will be entered. We might be the sort that enters Door #8 a ridiculous percentage of the time. But not 100%. That never happens with 12 doors.