$55 10lb steel co2 tank with 60% CO2 inside.
I left the hobby about 6 months ago and all the high tech setup I have left right here is this co2 tank. Is steel and it works great, well over 60% CO2 left inside. $55. We can meet up somewhere and trade locally. Not sure about carrying this tank on the subway. I would most likely drive there. If you live close by to me (brooklyn), I can drive it to your home.
Here is the tank ONLY. The hydro date is 2013. The tank is good until 2017.