This is an old thread but the question is still relevant and has been since the first cave painter asked for a rabbit to do a mural but agreed to do it for one berry and exposure amongst the top hunters of the tribe!
As a commercial artist, I have noted over the years that freelance artists are suffering because there are individuals within the collective who bring the rest of us down. They don't respect their own passion and dreams. They don't value the education and training they went through and it's cost in time and money. They don't embrace the commercial side of their chosen field and project a hobbyist aura instead of one of a competent professional. This lack of self value is perceived by clients and becomes fulfilled in how much they believe our work is worth!
Exposure is valuable, no doubt. And if you are willing to work for free or for peanuts to get it, there are many deserving pro bono projects and initiatives you could get involved in, and even then you would still invoice them so that everyone, yourself included, understands the value of the work you are giving away. If we all understand that work is work and demand fair compensation for it as individuals, the stock of all freelancers will rise and we will all be better off for it!
Check out these videos, they made me laugh (and cry inside)!