Sticks are found by the trees / in trees and a string can be securely tied to sticks, however, metal poles are slippery and string slides off the metal unless you punch a hole in it or use sap from a tree as glue to make the metal rod sticky.
Keep in mind that players can work cooperatively or competitively with each other. Players can undercut the vendor's prices and work competitively against the mobile vendor or use his prices as a reference point for values. When dealing with the vendor, you need to physically move to the vendor and a trade costs an action, but when trading with each other, you can send items across the maps at any time (except when in combat) and it is NOT an action. There is much advantage to form alliances and trade with each other! Businesses are encouraged!