Gas-station freebie (3)
I believe the answer is:
air
'gas-station freebie' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for air that I've seen before include "Broadcast - song" , "Mixture of gases needed for breathing" , "Bearing, manner" , "It's a mixture mainly of oxygen and nitrogen" , "Ventilate, give voice to" .)