[palish]

Only as a storytelling device. And in Deep Space 9, the Ferengi Nog was willing to spend his entire life savings of Latinum at the request of his friend Jake, just to buy Jake's dad a baseball card, simply to make him happy.

I hope one day I do something like that for someone. Maybe on my deathbed or something.

I don't know; I just wish people were... better people. To each other. I know they never will be, but I'd rather hope for this fantasy than accept grim reality.

[danilocampos]

And as long as we're geeking out, money existed but not in the Federation. So, not for humanity. Outside cultures had it, which made them an interesting foil for a humanity whose abundance taught them to value other things.

[lotharbot]

There's a little bit of ambiguity. Starfleet didn't use money, at least not explicitly, but there were humans who amassed personal fortunes, and other Federation worlds that had market economies. Money was also referenced several times in various Treks [0], sometimes with a character talking about how humans don't have money, and other times with a character talking about selling something, charging for something, or being willing to spend money for something ("I'd give real money if he'd shut up" - McCoy, referencing Chang's Shakespeare quotes, ST VI)

[0] http://memory-alpha.org/wiki/Money