Keeping a Finch

Question
I found a Finch yesterday in my neighborhood that couldn't really fly. I'm not sure how old it is, it can hop on the ground and kindof dart around a short distance but can't go high up in the air. I brought it home and put it in a cage but I don't know how to care for it or what to feed it. Also I was wondering if it's possible to keep this animal as a pet or if I should just let it go?  

Answer
I would buy wild bird food if the finch is one from the wild and not one that escaped from someone's house.
If it's wild, I don't recommend it. Wild birds don't do well in captivity. If I were you, I would try and find a bird sanctuary or some other place that it equipped to handle wild birds. I find that vets are the best bet for information on where one is. The yellow pages might as well.