Save 2000 Groschen by haggling.
To unlock this achievement you must haggle at least 2,000 Groschen from merchants when purchasing goods. This can be done gradually as you haggle throughout the game. Make a habit of haggling for everything, even the most basic of cheap essentials such as food.
Note: This achievement is advanced not only when purchasing goods, but also when selling. Simply persuade the merchant to purchase your goods for an increased price.