Pre-Gupta period refers to the period before the Gupta Empire in India. The most commonly used coin during this period was the Karshapana.

Karshapana
Karshapana was a silver coin used in ancient India. It was the most commonly used coin during the pre-Gupta period. Karshapana was a small coin with a weight of around 3.5-4 grams. It was minted in various shapes and sizes, and its value varied according to its weight and purity.

Other coins used during the pre-Gupta period
Apart from Karshapana, there were other coins used during the pre-Gupta period. They were:

1. Kakini - a small copper coin used in ancient India
2. Nishka - a gold coin used mainly for royal transactions
3. Suvarna - a gold coin used for trade and commerce

However, Karshapana was the most commonly used coin during this period.

Importance of coins during the pre-Gupta period
Coins played an important role in the economy of ancient India. They were used for trade, commerce, and other transactions. The use of coins also helped in the development of a standardized currency system, which facilitated trade and commerce.

Conclusion
In conclusion, the most commonly used coin during the pre-Gupta period was the Karshapana. It was a small silver coin, which was used for various transactions. Although there were other coins used during this period, Karshapana stood out as the most commonly used coin.