Introduction of coins, like the Tamil-Brahmi script, was another innovation of this period. People used coins at least in some contexts. The discovery of coin hoards of both local and foreign issues attests to the trade relations that existed between ancient Tamil country and other regions.
According to Monica Smith the distribution of coins with different weight standards in different region suggest their use as a standard of values and as a mediumof exchange.
Money economy had not yet developed, but the use of copper coins indicates monetization to some degree. The use of coinage could have limited to the urban centres or among certain traders.
We could argue that these coins were used as a kind of bullion in the sense that they had fixed a value based on the weight of the metal.
It has been argued that the Roman coins were used for bullion value. The Roman coins of Augustus Caesar’s time are found more frequently and they may have been picked up at a later time because of the high quality of the metal content.
The Roman coins are concentrated in the Coimbatore of Kongu region suggesting the importance of this region in the trade activities.
The later Roman coins are found more in the southern part of India and Sri Lanka. The Roman coins were also probably used as ornaments in this period and this is indicated by the indirect references in the Tamil literature.
Trade based on coins was also prevalent since the traders from far away regions had to a mass the wealth in metal. Although people traded in all kinds of materials, they finally converted their profit in the form of metal wealth.
The use of coins could be understood in the context of people travelling long distance and necessity for acquiring the wealth in the form of metals as bullion that could be easily transported.
Perhaps we need to visualize the pyramidical mode of exchanges and the coins were used at the top for main transactions by a limited number of people. Perhaps the coins were fixed value units.
The traders and the kings could have used the coins predominantly.
Local Coinage of Sangam
The local coins also had some value, perhaps the metal value and the kings could have minted them by smelting the copper and such coins might have been donated.
The Punch marked coins, Chera Coins, Chola coins, Pandya Coins, Malayaman Coins, are found all over Tamil Nadu. The Sangam literature also speaks about kasu, pon, kanam as various types of coins. Kasu was used as ornament, perhaps not in commercial transactions.
The chief Kalankaikkanni Narmuticcheral gave 40,00,000 gold coins to Kappiyarry kappiyanar. Another chief Atukotpattu Cherlathan gave Kakkaippatiniyar 100,000 kanam of coins. These coins perhaps had standard shapes and weight andthey helped to legitimize the king’s authority.