you can't actually buy oxygen or acetylene bottles, as they belong to the gas supplier. You need to find out who's bottles they are, apply for an account and get them refilled at a local depot.
paulie, you're onto what we call a two-bottle-shuffle. What you could do, although of course i'm not advising anyone to do this, as it would be naughty, is take out an account with BOC (if that's whose bottles they are), hire out another bottle, after a week or two, take back the empty and finish the hire. That way you get a full bottle for the cost of a months hire, plus fill charge and pick-up fee. For a low volume user it can save money. For a high vol user it makes no odds.
Just be aware that you are in possession of something that doesn't belong to you, so the risk is yours. BOC have been onto ebay sellers over the last few months advising them not to sell bottles which arn't theirs. Ebay prohibit such adverts.
Im with BOC Canada here and I have purchased 3 different kinds of bottles and all of which are completely mine and can be filled by any gas supplier here. Maybe the laws are different over there?
yes they are, you can only rent the refillable bottles here. This is, I think, because the gas supplier has to do regular safety checks on the bottles themselves.