It is very obvious that replicator usage is either free or rationed (Sisko talks about having used up all of his transporter credits to beam home every evening as a cadet).
I take that to mean that as a cadet, he had only a limited number of times he can use the transporter, which would be termed as credits, but I could be wrong.
Yep, if the usage of the transporter is rationed for Starfleet cadets it is also rationed for citizens (respectively they have to pay for it yet it is strongly implied that there is no money). Which is of course problematic, standard economics tells us that there are benefits from trading and it is reasonable to assume that the demand for beaming widely varies. Picard's brother or Bones probably wouldn't touch the thing on Earth whereas somebody who travels a lot has more need for it so rationing is inefficient.
The only way you can rationalize the economic world of Trek is via saturation. People are happy with what they have and do not get pissed off if a luxury good like transporter usage is rationed. If the world is full of Harry Mudds who want more just for the sake of itself (real world equivalents would be e.g. rich people who have several houses or cars which they cannot really use) this doesn't work or to be more precise, only as long as there are few Harry Mudds this world can be stable.
In every society there are social norms and if the dominant norms condemn greed you can keep the numbers low.
Let's also not forget that in the real world the hyperrich do not care about wealth / high income as a means for consumption but as a means for respect / power. This channel is absent in the world of Trek.