The words shekel kesef” are found over and over in the Torah. The shekel was originally not a coin, but rather a weight (mishkal), often of silver. For example, the shekel was the currency that Avraham used when he bought Ma’arat HaMachpela for 400 shekel kesef. Bnei Yisrael used the half shekel, machatzit ha’shekel, for the census to atone for their souls.
By the time of the Mishna and the Talmud, the shekel was a coin which was used alongside the dinar and the sela.
In Europe, there were coins that were minted by the Jewish community called “shekel dimyoni,” imaginary shekels. They were replicas of the shekels from the days of the Talmud. They were not meant for currency but rather for the mitzvot of machatzit ha’shekel and matanot l’evyonim on Purim as well as for Chanuka gelt and for the Pidyon HaBen ceremony.
In the modern State of Israel, in 1980 the currency became shekels (replacing the lira), and in 1985 the shekel was replaced with the New Israeli Shekel (NIS), which we use to this day.
I feel blessed to be living in Israel and to have the opportunity to use a variation of the currency that was used in the Torah and in the Talmud. We no longer need to make imaginary shekels to use for our ceremonies, as shekels are once again part of our daily lives.