30 pieces of silver is correct.

Matthew 26:14-16 – Then one of the Twelve, who was called Judas Iscariot, went to the chief priests and said, “What are you willing to give me if I hand him over to you?” They paid him thirty pieces of silver, and from that time on he looked for an opportunity to hand him over.

Matthew 27:9-10 – Then was fulfilled what had been said through Jeremiah the prophet, “And they took the thirty pieces of silver, the value of a man with a price on his head, a price set by some of the Israelites, and they paid it out for the potter’s field just as the Lord had commanded me.”

Many people are interested in how much that would be worth in today's value. It remains the matter of dispute and would be dependent on the amount of silver in the coins as well as the variable value of silver at any point in time.

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