Contradiction in trek.... 1st season TNG it states that the UFP doesn't use money...then, after that...Everybody uses Latinum for everything, through to DS9 and VOY. Which is reality? Which is canon?
Both. That's the problem with Trek -- inconsistency. There is another explanation (one our campaign uses); you get paid, but everything is credit oriented -- there's no 'money' persay, but there's still economy.
Supposedly (the explanation I remember) is that replicators and sentient equality made the idea of material weath passe. I don't buy it, myself. i think you can replicate necessities with no prob, but luxury items would be on a credit system.
The basic social system of the UFP is socialistic ("Every beeing gets according to his needs") with the state taking care of the basics (Basic clothing, basic food, housing, health care, schooling) without requesting compensation.
If you want more than the basics, you'll have to work. For this you get money. This money only exists in electronic form. Given the advanced technologie of the UFP, payment is done by letting a computer read your <techbla> field. This way, there is no need for physical money, credit cards etc.
When dealing with non-UFP civilisations, you have to change some UFP creds to an other currency (Cardassian Lek, Latinum...)
This way we have the "moneyless" society of TNG and the monetary sources for DS9 etc.
Jack/Nog searching for money can be explained as them not needing any (currently) with all basic needs being taken care of.
And this is what I love so much about the Star Trek universe. In the Federation you do not work to earn money, you work to further your self.
This is all great...but...I think it would take a lot more than 300 to 400 years into our future for humans to give up the concept of material wealth. We are getting there but at a snails pace.