Ancient Greeks had their own type of money, called coins. Coins were made of gold, silver, and bronze (like pennies). They had pictures on them like animals, gods, and goddesses for people to look at and know who they belonged to.
People would trade money for goods and services, like buying food or paying for a haircut. Sometimes, people would melt down coins and turn them into jewelry or new coins to make more money.
The Greeks made different sized coins for their different values, just like how we have different sized coins and paper bills for different amounts today. The biggest and most valuable coins were called gold coins, then there were silver coins, and the smallest coins were called bronze coins.
Some people would try to make fake coins (counterfeit) to trick people out of their real money, but the Greeks made sure to put special marks on the real coins so people could tell the difference between the real and the fake.
Coins were important in Ancient Greece because they were used to trade for goods and services, pay taxes, and make sure everything was fair in trade.