Ok so I know this is not free, but it's darn near it. Charlie (developer of Bullet Candy) is trying to raise some money to enter his new game Scoregasm and one of his newer games in the IGF. He is asking for donations, and he is awarding prizes for donations here are the prizes:
$1 - A copy of Bullet Candy Perfect
$10 - A copy of Scoregasm when it's released
$15 - A copy of Scoregasm and Beta releases
$25 - All that and he will include your name in the credits for both games
Now the $1 price for Bullet Candy is it's normal price, so you're not getting anything extra except the knowledge that you helped a good developer get more of his games acknowledged. I think it's a worthy cause and I've already donated. Though I'd love to donate the 10, I'm a little strapped for cash so I donated $5.