A tenner a month to the right charity can make a difference. A goat is pretty cheap, but makes a lot of difference to a family. A bag of seeds gives a farmer something to plant when the civil war is over and they can go back to their farm. Farming tools...plastic pipes for irrigation...etc.
I donate to a charity that goes to desperately poor places and hires locals to do stuff like laying irrigation systems, building a well, etc, then gives them tools, seeds, animals, building materials...for them to do the work themselves. That improves their self-respect a lot more than a handout every year. It's cheaper, too - a couple of years later and they don't need any more help.
An example...when I started donating, the appeal was illustrated by a man slowly dying in a mud hut in Ethopia, wondering whether his equally starving wife or their starving, sickly children would die first, wholly dependent on handouts and, unsurprisingly, profoundly depressed at his abject failure to support his family. He had some land, but that's no use without seeds or water. Two or three years later, they were illustrating the "this is what your money does" section. He works hard every day of the year, even sleeping in his fields at harvest time (to deter animals from eating the crops)...and he's happy as larry because his work irrigated his land, his work provides food for his family and some extra to trade at the market, he and his wife built their new home with their own hands, their children are going to school and he's just bought a camel, which is a sign that he's a wealthy man, a success.
That cost less than many people here spend on one component for their PC.
A little money to you is a hell of a lot to them, so you can make a difference without giving lots of money.
Giving blood is a good one more locally - you can save a life that way at no cost.