I just remebered: Hiker boxes. When you are thru hiking the Appalachian Trail, hostels, POs, everywhere hikers frequent has hiker boxes. when you get mail, or just go thru your pack, and find something you don't want, that is still good, you leave it in the hiker box. Food, gear, everything. Example: I am at the store, and don't want a whole tub of peanut butter, I just take what I want in my pack in my main container, mixed with jelly, and leave the rest for someone else to use. Or, I might find both in another town and use them from the hiker box and not have to $pend.
Too bad there's not much like that in real life...