I found someone selling some oxygen bottles on craigslist. I only knew that there were more than one, that they're mostly full, and it comes with one regulator. They said to make an offer.
$30 and a 6 pack of homebrew later I came home with this:
There are 9 of the smaller bottles (C) and 2 of the tall ones(E). Every one is completely full, except two of the shorter ones.
I know this is obviously more than I need, so I plan on getting rid of some of them. However, I want to make sure that I won't run out for a long time because I won't be able to get these refilled, and I'm going to sell my bernzomatic oxygen tank style regulator (someone in my club has expressed interest).