Charles Ellicott Commentary Matthew 26:15

"and said, What are ye willing to give me, and I will deliver him unto you? And they weighed unto him thirty pieces of silver." — Matthew 26:15 (ASV)

They made an agreement with him for thirty pieces of silver—The reward was a relatively small one, apparently about the market price of a common slave (Zechariah 11:12); but the chief priests (Caiaphas and his associates) saw through the man's sordid baseness and, as if scorning both his Master and himself, gauged their reward accordingly.