Freon Recovery

Not sure if there is already a thread on this one, but can anyone give a roundabout estimate on getting the necessary licenses to reclaim freon? I hate passing on window unit/metal cocktails, they seem pretty abundant certain times of the year. So I have a few questions:
1. What kind of license do you need to do so?
2. About how much cost upfront would it take, tools, gauges, and gear included?
3. I guess this goes with no.2, and of course depends on other things, but would it be worth it to me, a part time scrapper?
4.If I could find someone I could pay to remove it, would that outway the value in scrap? I know this depends on prices and weight, forgive me as I am not all that tedious when it comes to coming up with figures.
Thoughts?

Thanks, man. I am looking into that, but can you tell me if I can pick up needed tools and equipment cheap enough to justify it? I'm not trying to be ignorant here, just trying to figure out if anyone has gone this route for small timers like myself, and if it has turned out worth it for them.