If you have a local club or know of people in the area interested in an exchange you can simply meet in person. Shipping leaves is fairly easy too. Cut them from the plant, wrap the cut portion in a moistened paper towel. Take a piece of tin foil and wrap it around this. The tin foil keeps things in place. Put each variety in a small, labeled zip top bag. Pack the bags loosely in a box to avoid crushing. Priority mail is fine, but ship early in the week so they don't sit on Sunday. Don't ship when temps are in the mid-80's to 90's at either location without an appropriately-sized cool pack. Cold weather shipping requires some insulation, and possibly a hot pack.