Inside the federation, everyone can have what they want without restriction, that's the point of it. No one has anything more then anyone else.
Outside the federation it's a different story, the Federation would trade resources and services in exchange for the "local currency" like latinum or such.
Humanity "Betters itself" because it doesnt' need to focus on the here and now, fighting to feed themselves or keep themselves sick from disease, so they can focus on exploration and helping others. Anger, rage, theft, murder, all of which comes from the desire to "have something someone else doesn't", fundamentally can't exist in a society where everyone has everything.
"Not using currency" and "not carrying currency" are two different things. We know that there is a currency called "Federation credits"; therefore, "not needing money" refers to the lack of a need to carry bills and coins...that is, the Federation and its citizens use electronic funds transfer. In more isolated situations, Federation citizens may have to use latinum or darseks, the former being a gold specie currency, and the latter probably a fiat currency.
Utopian cultural and social theory or policy cannot replace economic theory or policy. The Federation has an economy, and there have to be and are modes and methods by which media of exchange are used. The remark that "the economics of the future are somewhat different", therefore, at most means the need to carry bills and coins are no longer necessary, and that there are accounts that are reconciled as a medium of exchange, and those accounts must have unit denominations, which we know to be, for the Federation, Federation credits ProfessorTrek 04:55, August 16, 2011 (UTC)
The old adage that is quoted as "Money is the root of all evil" is actually "The love of money is the root of all evil", and it's probably this social axiom that led Roddenberry to write a utopian vision into Star Trek. Although I believe that although "the economics of the future are somewhat different", it stands to reason that in a setting that uses Federation credits, or latinum, or darseks, for example, that economic token media of exchange are used. This means that some kind of economic philosophy and system are indeed used. Even communist and socialist countries had and have currencies, so even a planned economy does not eliminate the need for, and the use of, some type of currency, whether it be gold specie currency, fiat currency or gold-standard currency ProfessorTrek 14:44, August 16, 2011 (UTC)
As far as possessions, as in personal effects and belongings, go, we have seen those being used and possessed by various characters in a multiplicity of situations, carried in suitcases and briefcases, etc. It is possible that limitations of property interests are in place in the Federation; that is, that no Federation citizen can "own" anything that the state tells them that they cannot own (which is one of the tenets of communism).
I think that this is not the case, however. We saw Kirk remark to Picard in Star Trek Generations, about his house, that "...it's my house...". Thus, there still is an understanding of personal property and real property interests. Picard once said that he does not "own" the Enterprise-D, so he recognizes property interests accruing to persons.
Thus, in addition to references to a currency medium of exchange, there are also property interests in tangible objects, and, it's more than likely intangible objects too, that accrue to individuals in the Federation, such as intellectual property, for example. Given those unavoidable conclusions from dialogue, it is difficult to reconcile what Picard said to Ralph Opfenhouse in ST:TNG "The Neutral Zone". What they had to have been referring to were financial interests in securites such as stocks, bonds, equities, etc. Why those no longer would exist does suggest a planned economy.
What also makes sense is that if literally any quantity of almost anything can be manufactured by replication and moved by teleportation via the transporters, and, by warp-driven vessels, economic theories such as that of supply and demand, at least as to tangible objects or goods would be much less a factor in Federation economics. It would be an entirely different situation as to supply and demand of services. For example, what good is having a medical body of knowledge, expertise and technology that can treat or cure almost any ill if there is no physician around to adminster it? That being said, freedom from some want and freedom from some adversity for essentially all members of society does suggest a much more utopian society ProfessorTrek 15:08, August 16, 2011 (UTC)