I got mine from Airgas today for $95 filled. That was the cost for the initial tank plus the hydro test? I think thats the name. Anyways, when the tank is empty you bring it back and exchange it for a new tank and pay $18 for the refill and test again. I know it's cheaper to just get the same tank filled over and over, then have it inspected every few years but I don't have that option where I live.
I know they only give out aluminum tanks, so that is a huge bonus! Oh, and don't bother with Norco. They are more expensive then airgas. It seems like most cities either have one or the other, or both.