W-9 question

I'm a full time volunteer, getting room and board but no money, so I don't currently pay income taxes. I am interested in freelancing to earn a small amount of money--say $200/$300 yearly. eHow and many Elance providers want W-9 forms from writers. If I fill out a W-9 form will I be required to fill out an income tax return even if I don't make enough to owe taxes?
Yes, I know it's an odd situation and this may not be the place to ask. If anyone does know about this I'd greatly appreciate info.