Public Benefit Flying
I rent my planes for all the Angel Flight, PALS and Veterans Airlift Command flights I do. The rental company even gives me a 10% discount on the rate. So, yes, you have to supply the plane, but you don't have to own it. With Uncle Sam picking up a goodly portion of your costs (they're deductible, you know), it'll be the cheapest and best flying you'll ever do.
So, get yourself checked out someplace and jump through the few hoops these organizations require and get to it. You have the right attitude and desire.