Commodities are considered those goods which have a universally valid price or value. For example, petroleum is a commodity which does have a well determined starting price, but which goes up or down depending on many surrounding factors (market fluctuation for example). Another important factor in settling the price of a commodity highly depends on the competition which is going on. Products which can be found on the top of the list as commodities include: oil, coal, sugar salt, precious metals (silver, gold and platinum), and coffee.