jwolthuis - 12:55 am on Jun 9, 2011 (gmt 0)
Sorry for the nitpick. The OP was concerned about method of shipping and cost, so I flamed when I saw the 25 lbs vs 2 lbs comparison. My misunderstanding.
OP: What is the gas? We can talk all day about surcharges, but it all depends on if you're shipping "air" (Class II Div 2.2) versus "ammonia" (Class II Div 2.3).
One is shippable via UPS, FedEx, USPS, and the other can't be shipped without a HazMat license. We need to know the type of gas to give you any logical advice.