For thirty pieces of silver Judas Iscariot helped send Jesus to the cross, and then hung himself for this dastardly deed.
Luke 22New International Version (NIV)
Judas Agrees to Betray Jesus
22 Now the Festival of Unleavened Bread, called the Passover, was approaching, 2 and the chief priests and the teachers of the law were looking for some way to get rid of Jesus, for they were afraid of the people. 3 Then Satan entered Judas, called Iscariot, one of the Twelve.4 And Judas went to the chief priests and the officers of the temple guard and discussed with them how he might betray Jesus. 5 They were delighted and agreed to give him money. 6 He consented, and watched for an opportunity to hand Jesus over to them when no crowd was present.