Not much trade in the Dark Ages
Then trading started again
After the Dark Ages, people started to use iron, and that made them richer.
Trading started up again. People went back to raising sheep rather than cattle, and they began to make wool cloth, and to trade and fight again.
Mercenaries and money
Because they were mercenary soldiers, by the Archaic period Greek men learned about minting coins from the Lydians they fought for in West Asia, and soon each Greek city-state was minting its own coins.
Who did the Greeks trade with?
As the Mediterranean region recovered from the Dark Ages, the Greeks and the Phoenicians sent out many groups of settlers to colonize (conquer and take over) southern Italy, southern France, Spain, and North Africa.
Greek trade to the East
Greek traders bought glass beads, medicine, spices, silk and papyrus from those people. Further north, around the edges of the Black Sea in Central Asia, Greek traders bought wheat and barley, cattle and horses, wood and slaves from the Scythians, and sold them pottery, wine, iron and bronze tools, and linen.
Learn by doing: on a map of the Mediterranean and Black Sea, show what is being traded and where
More about the Classical Greek economy
Trade & Warfare, by Robert Hull (2000).
The Ancient Economy by Walter Scheidel, Sitta Von Reden (2002). A collection of essays by different specialists, but written for the non-specialist.
Economy and Society in Ancient Greece, by Moses Finley (revised edition 1983).
The Dark Age of Greece: An Archeological Survey of the Eleventh to the Eighth Centuries B.C., by Anthony Snodgrass (2000). Snodgrass thinks that an increase in population caused most of the changes of the Archaic period.
Warriors into Traders: The Power of the Market in Early Greece, by David W. Tandy (2001). More controversial; Tandy argues that Greek colonies were founded by traders, not because there were too many people living in Greece.
The Greeks Overseas: The Early Colonies and Trade, by John Boardman (2nd edition 1999).