I always carry an extra pack of cigarettes with me.
If I were homeless, I would want cigarettes to pass the purgatory.
I carry it not only because I can easily smoke that much, but because I never have spare change or cash - I give out cigarettes. If they have a real good pitch, I give them the entire pack. You never seen such a happy face, in fact, I get no smiles or real joy when I give them a buck or two - but they are VERY happy when I give them 5 or 6 cigarettes.