I do have one lying around....but I'm honestly hesitant to encourage you to buy a used helmet off the internet. You're taking somebody at their word that the helmet's integrity hasn't been compromised. Without suggesting anybody on TE's boards is dishonest, I'm not sure I'd trust my head to a stranger. Plus, there's no guarantee that the helmet will be packed correctly and not compromised during shipping. Keep in mind that you a helmet that has been compromised in some fashion may look just fine to the naked eye. Finally, there's the question of fit. Unless you know that a particular brand and style fit you, you have no guarantee that the helmet will work with your head.
I'm not sure how much you're willing to pay for even a used helmet, but my advice is go to your nearest LBS and get a helmet that's on the cheaper end of the spectrum. It may have fewer vents than an expensive model, but from a safety perspective it will work just the same. I'd second looking into Bell's 30% off policy, too. Bell and Giro are owned by the same company, so I would assume that Giro offers the same discount. Beyond that, there are pretty cheap deals on helmets to be had at Nashbar and Performance. They're always offering special discounts, too. If you know what brand helmet fits you well, you could probably select one that will fit without the benefit of trying it on.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher