Since this guy's fishing too why not make a slot for every character where they can put the item they wanted to sell and price it,5 slot for one character is more than enough to sell their stuff.
And when the item is put into shop Slot there should be some kind of sign/signal or notice on top of the head of a character that's selling items,s o that other player would easily notice it and browse the sellers item through clicking the

With this we can minimise the use of chat window when selling items,sometimes its hard to catch-up to whatever their selling when theres to many people selling their stuff too.
PS.if skin is not good,gold works too!