Best way to Chip-in?

Hey all! I'm a jealous non-traveler. I would love to ditch everything and hitch across the country, but I've got a nice grad-school thing going right now. My question is, what is the best way to help out you guys? I don't run across travelers very often, but when I do, I try to do the basic things like chip in a dollar or two, buy a meal, etc. Is there anything else I could be doing that the average person wouldn't think of? I dont have any special resources right now, but I'd love to help out when I can!