If you pity and want to rescue people do so in a manner that does not involve any codependent way (don't know if you are a codie). I sign a lot of petitions that help people's issues and it is free.
I, too, want to help humanity. I do it by putting $5 of each grocery shopping trip into food for the food bank (I used to donate blood since that was completely free and VERY useful, but they changed the rules on how long you could live in Europe due to mad cow disease, and I'm not eligible anymore - I was 1 pint short of 2 gallons when they changed the rules). I use every coupon I can find and try to get as much as possible for my $5. I figure that's not much different than a cup of coffee anymore, so it's not a lot of money, but it's some.
I also donate my unwanted stuff to places that give (or practically give) things to people who are in the greatest need. Thankfully, where I live, there are a lot of such places who need items to give to people who are trying to set themselves up in a household after some catastropic event (be it addiction + rehab, fire, domestic abuse etc) has left them on the verge of homelessness, or are actually homeless and trying to not be. Many a piece of old furniture has gone to someone who really needs it. Since I don't want it anymore, I figure it doesn't matter who gets it AND it helps with landfill usage.
I have learned to only give to those who aren't asking me directly. Those around me know that if they ask, the answer will probably be "no", but if I see a need, I will probably volunteer (I once offered a co-worker who was on very limited income $20 to go get her tires rotated because her front tires were completely bald - she refused, but she appreciated my concern for her). I'm no longer trying to rescue those who just don't want to take care of themselves. Instead, I'm trying to help humanity as a whole as best I can.
It's a good way to vent off some of my needs to make the world a better place, but do so in a healthy manner.