Dedicated Trade System

Anyone know of a tutorial or description on how to implement a player to player trade system. Player A requests a trade to Player B of they agree to trade it opens up a slot window each player can add items to the slots and it shows other the other players screen what they are wanting to trade. If player A or Player B accepts the trade it notifies the other player once both accept the items are transfered. If no tutorial exists I would be willing to pay for such a system haha.

have you found anything for this ?