Free Culture is not about art that is free of charge, but art that is free from encumbrance or burden.
Free Culture fully embraces the idea of musicians or any other artists, being paid for their work, and being able to sell their work.
Free Culture simply means that people who’ve obtained such work legitimately are not constrained from reproducing it, reselling it, repackaging it, sampling it, or making derivatives, and certainly don’t have any obligation to pay royalties.
Nevertheless, the choice to charge or not charge for their work still remains with the artist. Free Culture does not require that artists must work for nothing, nor that their work and copies thereof can never be charged for. Anyone can walk into a shop, buy a copy of RedHat Linux, produce two copies, keep one, and sell one of them to a friend – without committing a crime. However, they would still be guilty of shoplifting if they didn’t pay for the shop’s copy.
The key distinction of Free Culture is about unconstrained copying and derivation, not that everything must be free of charge. Thus, among other things, the choice to charge or not charge for copies, now rests with the owner of each copy, and not the original artist (a privilege copyright was supposed to confer).
There may well be some obscure puritanical movement that seeks to define a certain sacred form of art that must be prohibited (legally or otherwise) from involvement in any barter or financial transaction throughout its entire lifecycle, whether to the artist’s or anyone else’s benefit. However, that is not the Free Culture movement.
You are always free to charge for Free Culture.
There are art movements that encourage people to make and share art through participation not publication or promotion (eg see Hakim Bey’s writing on ‘immediatism’), and political movements like the situationists (and certain flavours of anarchists) who believe that in the ideal society art (and everything) would be shared free of charge. However, in all the cases I’m aware of, they see this as coming about through the majority of people voluntarily changing the social agreements about how art and exchange work, rather than any kind of ban being imposed on currency, markets, and trade.
Even the Soviet Union using rationing tokens of some kind to mediate the exchange of scarce items, and was totally unable to prevent a thriving black market in consumer goods, just as most countries today are totally unable to prevent the black market in recreational drugs.
It’s really the other way around.
Society is naturally at liberty to share cultural and technological knowledge, and to exchange labour for whatever the market will bear, e.g. to write a song for money.
So it is not society that makes the rules against this natural order, but government, and it does so with the pretence that it is by the will of the people, or by their consent, that the people surrender their liberty to share and build upon their own culture, that the state and its corporations may profit from the consequent monopoly rents they can exact (selling people that which they were born with, their liberty, back to them piecemeal – qv ‘license’).
It is copyright and patent that are ‘black’. Thus a market that ignores or lacks such state monopolies is a free market, not a black market.