One player lists an item. Another player pays with Pix. The payment stays tied to that purchase until the game delivers the item.
A player puts an item up for the other players. The buyer pays the listed price plus the fee. The listing and the delivery happen in the game.
The Pix is tied to the purchase. The game delivers the item of that purchase. The terms of PokePix describe the deadlines and what happens if the trade does not complete.
The fee is 10% and the buyer pays it, on top of the item price. The number comes from the same configuration as the game.
