I should probably add on the Gold Pressed Latninum issue. Moneyless systems don't work well in systems where there is money. Supposedly, the Federation of the 24th Century is a society where everyone has everything they want, and just need to order from the Replicator something new. The only really valuable stuff comes from things that can't be replicated. Latninum is one such thing. But now here's where it falls on its face. Fuel still costs, something. If not money, then what? If fuel were free, then you'd never have to worry about range on a Starship, because you could just keep replicating more fuel. Parts break down? Replicate a new part. TNG writers look back on Roddenberry's Replicator as the worst thing ever "invented" because of this very thing. The Federation kind of took a step back in society because it falls back on a barter system, rather than currency. Currency was usually first introduced because a farmer couldn't trade a rancher enough food for an ox. Instead the farmer sold 50 other people food, for which they gave him currency, so he could go to the rancher and trade him the currency for the ox.
Putting the Federation aside for the moment and not dealing with their lack of money. It's very clear that all the other powers do use money. It's mentioned by every race, Klingon, Romulan, Cardassian, Dominion member, Bajoran. Now of course, all of them use their own kind of currency, and an exchange rate is determined based on, among other things, the likelihood of doing business with them in the future.