However, most of the time I'm met with scepticism. "There's no way that just by clicking a button, you can send food to starving people or protect the rainforest." "There's got to be some kind of catch." And so on.
Weeeeell, I just happened to be browsing Snopes.com, the biggest name in proving/disproving myths, rumors, and urban legends. While using the "random story" feature, I stumbled across this article. Check it out for yourself: it's all legit.
So, now that the skeptics out there don't have an excuse not to, be sure to check out the following sites. One links directly into the rest, so you can literally click each of the donation buttons in under a minute. You're online anyway, and you gots nuthin to lose.
Also, check out FreeDonation.com and EcologyFund.com for similar save-the-world-for-free sites.