My hypothesis is that The Federation has two currencies:

1) One for "domestic" use, based on a Social Credit system (or something like that), which would explain post-scarcity while there is still a free market.

2) The other is for trading with other Empires/alliances/federations/etc, a hard currency similar to gold or silver standard, but instead based on a metal valuable in the world of Star Trek.

"Batman is only meaningful as an answer to a world which in its basics is chaotic and in the hands of the wrong people, where no justice can be found. I think it's very suitable to our perception of the world's condition today... Batman embodies the will to resist evil" -Frank Miller

"Conan, what's the meaning of life?"
"To crush your enemies, see them driven before you, and hear the lamentations of their women!"
-Conan the Barbarian

"Well, yeah."
-Jason E. Perkins

"If I had a dime for every time Pariah was right about something I'd owe twenty cents."
-Ultimate Jaburg53

"Fair enough. I defer to your expertise."
-Prometheus

Rack MisterJLA!