At the beginning of the game, prices of all commodities are at set values. Generally resources are valued at $100, materials at $300, and goods at $900.
Prices are recalculated every turn prior to deals being offered. If demand outstrips supply, the price rises. If there is a glut, the price falls.
The new world price is used this turn and appears on the trade screen next turn as a basis for next turn's calculations.
