The half-shekel is a traditional Jewish practice first commanded in the Torah for every Israelite to contribute a half-shekel to support the service of the Mishkan, and later the Temple. This contribution helped support communal religious life and ensured that everyone, regardless of status, took part.
Today, as a rememberance of the commandment despite not having a Temple, the Jewish custom is give a donation in the amount of a half-shekel (or its modern equivalent) on the days before the holiday of Purim.
In Jewish thought, the significance of the “half” shekel symbolizes that no individual is complete on their own and only becomes whole when connecting with others, and ultimately with God.