|This item really only makes sense in Multiplayer. You could craft it alone if you really wanted to, but what would be the point of that?|
Light and Darkness, Day and Night, good and bad, Yin and Yang... Item-O-Mat and Sell-O-Mat.
Whereas first one will sell stuff from the chest, gathering money, latter one will BUY items.
It is set up similar, with a chest and coins in the last slots of the chest to determine the price (per bought item).
However, you will as well need to place a single piece of the wanted good in the first slot of the chest, to tell the Sell-O-Mat what it is supposed to buy from players.
Of course, you need to provide enough money within the chest, as well. Coinstacks can be used here, too.