Nitrogen bottles

Is it legal to sell N2 bottles? I heard that since they are regulated by public transportation that you can't legally sell them. True or false?

From what I understand, if someone's name is own the bottle, say AirGas or something, I don't think you can sell it. Here they are very strict on filling bottles. If it isn't their bottle and they fill it, they could be fined I believe. BUT, if you have paperwork saying that you bought the bottle, then i think it is ok to sell it. Don't quote me on any of this though

What size you wanting to sell?