Almsgiving...

Is it true that your left hand shouldn't know what your right hand is doing? Do you donate to buy influence? What if you just want to influence other people to give? I can say I've been inspired by friends who do something good to help others, say by volunteering in a Motherless Babies' Home or something, and wouldn't get that inspiration if they didn't tell me...
I was thinking of giving money for something at school and I'd want people to know about it but I also feel it's more stylish to donate anonymously. I probably will end up not making this donation at all, I'll save the money and give moral support, really...but the questions stand...if anyone is not too shy to write back.