Amazon is doing one of their semi-annual sales on Firefly. So right now you can get a DVD Boxed Set of the series (all 14 epsiodes) for $13.49 which is a pretty good deal if you don’t have it, or haven’t seen it yet. Why wouldn’t you have seen it yet?
Of course if you have Amazon Prime you can actually stream all the episode for free. And if you don’t have Amazon Prime… you could always sign up for a 30 day free trial. It definitely won’t take you 30 days to watch Firefly.