

They don’t have what we would recognize as an economy, but they do have resources and are on rare occasions willing to trade them with outsiders. (See: Voyager) I can imagine some particularly risk-inclined ferengi trying to strike a deal. Gives me a “goodlife” from Saberhagen’s Beserkers kind of vibe.
That’s kind of important to the story though.
spoiler
V starts off thinking she’s dying and her mind is changing and she doesn’t know how long she’s got, and by the end she’s learned that everyone is dying and everyone is changing all the time and no one knows how long they’ve got. The only real choice is whether you use the time you’ve got to live, or don’t.