It's the thought that counts - whether it's Christmas, a birthday or a charitydonation.
Sometimes, especially when you're young, you see a news item covering a natural disaster, or an ad for charity and you think there isn't any point in you making a donation because, "I don't have much." To somebody that needs help, though, your "not much" is a whole lot. So even if it's only £5 (and really, how much can you do with that?) donate it to a charity that's helping the sufferers of the Haiti Earthquake and let it do something worthwhile. And get all of your friends involved, as well - you'd be surprised how quickly you could raise some money.