How Did Judas Die?

Judas hung himself, and then died.

Then Judas, which had betrayed him, when he saw that he was condemned, repented himself, and brought again the thirty pieces of silver to the chief priests and elders, Saying, I have sinned in that I have betrayed the innocent blood. And they said, What is that to us? see thou to that. And he cast down the pieces of silver in the temple, and departed, and went and hanged himself. And the chief priests took the silver pieces, and said, It is not lawful for to put them into the treasury, because it is the price of blood. And they took counsel, and bought with them the potter's field, to bury strangers in. Wherefore that field was called, The field of blood, unto this day. Then was fulfilled that which was spoken by Jeremy the prophet, saying, And they took the thirty pieces of silver, the price of him that was valued, whom they of the children of Israel did value; And gave them for the potter's field, as the Lord appointed me.
- Matthew 27:3-10 (KJV)

The chief priests couldn't use the money, because it was blood money, so they bought a field to bury strangers in. This may well have been the same field where Judas hung himself in.

Then some say there is a "different" account in the book of Acts.

Men and brethren, this scripture must needs have been fulfilled, which the Holy Ghost by the mouth of David spake before concerning Judas, which was guide to them that took Jesus. For he was numbered with us, and had obtained part of this ministry. Now this man purchased a field with the reward of iniquity; and falling headlong, he burst asunder in the midst, and all his bowels gushed out. And it was known unto all the dwellers at Jerusalem; insomuch as that field is called in their proper tongue, Aceldama, that is to say, The field of blood.
- Acts 1:16-19 (KJV)

Is this is a different account?!?

No, it is not. It only says that when Judas hung himself that at some point he fell on his face (because the cord broke).

There is actually a third account written by Ellen White.

Later that same day, on the road from Pilate's hall to Calvary, there came an interruption to the shouts and jeers of the wicked throng who were leading Jesus to the place of crucifixion. As they passed a retired spot, they saw at the foot of a lifeless tree, the body of Judas. It was a most revolting sight. His weight had broken the cord by which he had hanged himself to the tree. In falling, his body had been horribly mangled, and dogs were now devouring it. His remains were immediately buried out of sight; but there was less mockery among the throng, and many a pale face revealed the thoughts within. Retribution seemed already visiting those who were guilty of the blood of Jesus.
- Ellen White, The Desire of Ages, p. 722

And who paid for the field? The chief priests, or Judas?

Both really. Judas threw the money into the temple, but the chief priests didn't want it, so they bought the field "on behalf" of Judas (with his money).

Do we need to feel sorry for Judas?

I don't think so. He was with Jesus for three and a half years. Jesus would have tried everthing to save him, but I think he just didn't want to be saved. He just was not interested in what God had to offer. It was his choice.

Jesus said to him, "Friend, wherefore art thou come?" His voice trembled with sorrow as He added, "Judas, betrayest thou the Son of man with a kiss?" This appeal should have aroused the conscience of the betrayer, and touched his stubborn heart; but honor, fidelity, and human tenderness had forsaken him. He stood bold and defiant, showing no disposition to relent. He had given himself up to Satan, and he had no power to resist him. Jesus did not refuse the traitor's kiss.
- Ellen White, The Desire of Ages, p. 696

Sad, sad, sad...

The Son of man goeth as it is written of him: but woe unto that man by whom the Son of man is betrayed! it had been good for that man if he had not been born.
- Matthew 26:24 (KJV)