The Sumer civilization is the first known use of commodity money where something symbolized another thing of value. Hammurabi's Babylon embodies the first known instance of a modern economy, and his famous code embodied the laws.
Before "money" people barely scraped by...
In instances where places do not have a monetary system a commodity almost always becomes the "money" itself. We can look at microcosms like a prison (cigarettes) or new colonies like New South Wales where rum took on that spot until enough coinage came into the area.
In places where this doesn't happen, often people are hampered in trade because of timing of the markets. Fruit and grain do not ripen at the same time. Hence the need for, at the very least, commodity markets where a commodity that doesn't rot can be used for interim holdings... that commodity becomes the "money" of that area.
