I have purchased my cylinders from the local supplier with no problems. I laugh at craigslist, sometimes because Blue and Red welders are posted fore more $$ then some new welders are sold for at the local weld store around here. In Arizona there is good deals on craigslist for cylinders, 220 CF cylinders typically go for $140-160 some are full. As I posted before the 220 CF bottles in Arizona from the local stores are about $220 and if you have the good guy price that I did not state earlier they are about $160 (same price for 150 CF bottles currently because they cost my local supplier the same amount). I would look up the local suppliers and call around. Ask for their prices and see who has the best deal. Also, ask for the refill prices. Some of these places are flexible, do not get ripped off like my friend who paid $40 for a refill on a mixed 60 CF bottle.