Gift giving: Gift-giving was another important form of exchange in early civilizations. Gifts were often used to establish relationships, cement alliances, and smooth over conflicts. For example, a chief might give a valuable gift to a neighboring chief in order to gain their favor.
Credit: Credit was also used in early civilizations, although it was not as common as barter or gift-giving. Credit allowed people to buy goods and services now and pay for them later. For example, a merchant might sell a shipment of goods to a customer on credit, with the understanding that the customer would pay for the goods once they had sold them.
Currency: The use of currency, such as coins or paper money, developed later in human history. Currency made it easier to trade goods and services, as it eliminated the need for bartering or credit. The first coins were minted in Lydia, a kingdom in western Anatolia, in the 7th century BC. Paper money was first used in China in the 11th century AD.
These methods of trading allowed early civilizations to flourish and interact with each other economically.