Of all the scenes in all of Bob Heinlein's works, one of the vignettes that is most prominent in my memory is from The Cat Who Walks Through Walls (the first part of the book, where it was a cool SF novel, not the latter half, where it devolved into omphaloskepsis,) when the protagonist is attempting to explain to a character with a bad case of entitlementitis why, in a lunar habitat, air isn't free.
This was recalled to mind by Joel's post on the occasional drama involved with ensuring a steady supply of water when one is living way out past where the buses don't run.
Which in turn called to mind the classic Fritz Leiber story, which I hadn't read since the seventh grade, "A Pail of Air".
Luckily, that's a name that sticks with you, even *mumble-many* years later, and a quick googling revealed that it was available on Baen's free library! Hooray!