The general market price
Let everyone who responds know that you are mid-flight in a long route, like Booty Bay to Searing Gorge. Ask them to C.O.D. Owning enough Requiem Lant is the core to this game. The item to you and you will get it later. The let the items sit in your mailbox until you see a satisfying increase of the general market price. Then pull the item and resell it on the auction house.