To avoid further misunderstandings, I am "free" -in any case-, in a general sense. (that i´m not, btw... who is 100% "free"?).
When I added the tags "disponible" / "available" it is because this is the sign that taxi cabs use here in their window shields to let you tell if they are with a passenger or available. (turned on like in here is "available", obviously, while turned off becomes invisible from a distance and means the car is busy.)