Here are some places for gas near where you live:
Link
Sorry,

I wanted to be cocky because I initially really thought your thread was actually about "where to buy gas."
What's green gas anyways? All my guns use CO2.
Yeah, in all seriousness Riddick's green gas prices are the best. Certainly unbeatable. I was suspish the first time I saw it for sale. But great stuff. I'm using a can in my Sig now.
I know it usually works pretty flawlessly, but I've had some problems with the camping style propane & adapter. It will be cheaper and (I have heard) show an increase in PSI by a bit.
However, the adapter that my dad has doesn’t quite seat to the seal on my mag perfectly, so when I fill it, I’ve had problems with the O-ring flying off. Very unfortunate for as small and impossible to purchase those things are. Little grievance, but it’s led me to take more comfort in buying green gas. Besides, everyone likes the smell better hehe.
Regular raw-egg propane actually makes me salivate because it reminds me of campground meals.