Nocks is not a store that hangs a pricetag on a product at a price they see fit.
It's an exchange where the price is determined by supply and demand.
See
https://www.nocks.com/trade/NLG-EURNow as an extra service you can buy Gulden at Nocks using iDeal or Bancontact but that's a frontend where you actually do a marketbuy on the exchange.
That begs the question, where does the NLG come from? Nocks is the seller. They may call it different things now but that was the setup