Green gas is a complete waste of your hard-earned money.
It is the exact same thing as propane.
You have to buy an adapter, and then you can guy your propane from Canadian Tire in green Coleman cans.
With regards to BBs, you will need to buy high quality ones, NOT .12s, to not damage your gun.
DO NOT reuse them! They will have slight inconsistencies from being fired and hitting whatever target, and these inconsistencies can ruin your barrel.
However, I'm sure not sure why you would want to. Do you plan on picking them up of the field after a game? Or did you mean after plinking?
God is a /b/tard.