In terms of today's money, what would be the value of the biblical half shekel?
Maimonides writes (Laws of Shekalim 1:5) that the half shekel mentioned in the Torah – the annual contribution every Jew was required to give to the Temple coffers – is equal to 160 grains of barley, which, in modern measurements, would be approximately eight grams of silver.
It is impossible to know silver's value in biblical times. At today's rate of approximately 17 US dollars per ounce, 8 grams of silver is around five dollars.
Rabbi Eliezer Posner