Have to agree with demacoz,my gas account is with BOC but i changed from a yearly account to a monthly account for two reasons,1 easy to budget monthly and 2 i can return bottle when empty/not in use and not get screwed.The monthly fee is $14.04 being E size
I have found it more benificial doing this also as time tends to get away and you can have bottles sitting around that get forgotten about when not much is going on in the build department.
As for gasless welding,i'm yet to see one i would pass as a motor sport scrutineer....but i live in hope