Only give it to someone who is willing to allow you to visit their home (which is unlikely in light of the recent "Craigslist murder").
I acquired my bird from Craigslist. She had been purchased as a very young chick from an aviary that was about to close down (and thus couldn't finish her and her siblings' handfeeding) by someone who raised her up a bit, weaned her, and sold her to me, so she was not really a secondhand bird, as I was her first real permanent owner. I've had her for two and a half years and love her to pieces and am so incredibly thankful that I found such a wonderful bird on there.
*However*, I do realize that our success story is not the story of all birds, and in retrospect I probably would never have bought a bird from someone who didn't care enough to at least make sure I knew my bird basics. Make sure whoever you give the bird to is really right for the bird and knows how to take care of him.
The best option would be to give the bird to someone you know in person, but if that is not an option, Craigslist is not *always* a horrible choice, though it can unfortunately turn out that way.