In the Bible, it is mentioned that Judas Iscariot was paid “30 pieces of silver” to betray Jesus to the Jewish authorities, ultimately leading to his arrest and death.

According to Wikipedia, there are four possible candidates for the “pieces of silver” used to pay Judas. They are the Tyrian Shekel, the Antiochan Stater, the Ptolemaic tetradrachm, and the Athenian tetradrachm.

Among them, the Ptolemaic tetradrachm has the lowest silver content, at 25%, and hence 30 pieces of Ptolemaic tetradrachm would be worth around 90 USD at today’s silver  spot prices. The other coins had higher silver purity and were worth around 300-400 USD at today’s silver value.

The Athenian tetradrachma was equal to the value of 4 drachmas; a drachma was supposedly the daily wage of a skilled labourer; hence “30 pieces of silver could be worth 120 days wages.

In Matthew 27, it is mentioned that Judas, feeling extremely guilty, later offered to return the coins to the chief priests. However, the chief priests refuse to accept it, and Judas throws the money into the temple and later hangs himself. The money is then used to buy a field as the burial place of foreigners.

Other mentions in the Bible include:

•  Zechariah is paid 30 pieces of silver and he “threw them to the potter” (Zechariah 11:12-13, NIV)
• 30 shekels of silver is the compensation if a slave is killed by a bull. The owner of the bull has to pay this amount to the owner of the slave. (Exodus 21:32, NIV)

However, the silver coins mentioned in other parts of the Bible are not the same as the ones used by Judas and probably have different values.