Nothing new here, of course, but it bears repeating: Don't just work for free without carefully considering it:
People who would consider it a bizarre breach of conduct to expect anyone to give them a haircut or a can of soda at no cost will ask you, with a straight face and a clear conscience, whether you wouldn’t be willing to write an essay or draw an illustration for them for nothing. They often start by telling you how much they admire your work, although not enough, evidently, to pay one cent for it. “Unfortunately we don’t have the budget to offer compensation to our contributors...” is how the pertinent line usually starts. But just as often, they simply omit any mention of payment.
Personally, I'm happy to write and contribute for friends and acquaintances (within reason), and I've been known to politely refuse token payments for small publications after delivering a story. Note, however, the vast difference between politely refusing a $20 payment and being expected to deliver a story or article for free, even when the net financial change in my wallet is $0. It's about expectations and professional respect.
Practicalities aside, money is also how our culture defines value, and being told that what you do is of no ($0.00) value to the society you live in is, frankly, demoralizing. Even sort of insulting. And of course when you live in a culture that treats your work as frivolous you can’t help but internalize some of that devaluation and think of yourself as something less than a bona fide grown-up.
I'm, like, totes a legit grown up, though, I'll have you know.
Read the full article here: http://mobile.nytimes.com/2013/10/27/opinion/sunday/slaves-of-the-internet-unite.html
Look at an entertaining flowchart on how to determine if you should work for free here: http://www.shouldiworkforfree.com/