I know a lot of artists who draw really well, and put their stuff up online for free. They then take comision requests that they charge money for which they use to live off of. The free art is an advertisement; a demonstration of their skill. The custom job is what they get paid for. Musicians can, and often do, get paid the same way. They give their music out for free to advertise their skill, a radio station can "hire" their skill if it's good enough, then the radio station pays them to keep producing music while advertising supports them playing it to everyone else for free. Likewise, I keep hearing that big name musicians make mst of their money from actually doing work at concerts as opposed to CD sales.
Here's a question though. If someone was selling me a car, and telling me how it has really nice features, is very reliable, and is a lot of fun to drive, but not allowing me to see it, then when I pay, say, $20,000 for it (average car price), it turns out to be an old, beat up, stripped down piece of crap that only goes straight forward and barely moves, is it fair that I am not allowed to return it, and the sales guy is legally allowed to get away with it?