Per my post on the Weekly Update:
Quote from: Morgenes on the Weekly UpdateItems in shops have a random chance of being virtually sold
There is now a chance that every hour a shop is open items in the shopkeepers inventory will be 'virtually' sold to vNPCs. This is not a huge chance, but over time it will put a mark on the economy.
As items sell off merchants will have more money to buy items, as well as hopefully reduce duplicates of items, allowing crafted/foraged items to be sold to merchants.