It is difficult to accept that contradictions can exist in the Bible, yet this is one of them. Raymond E. Brown says, in An Introduction to the New Testament, page 114, that Luke's account of the death of Judas in Acts 1:18-19 is scarcely reconcilable with that in Matthew 27:3-10. If they can not be reconciled then one or both accounts are not really historical and it then becomes a moot point whether we choose to say that the priests bought the field of blood, Judas bought the field, or even blend them in a rather implausible combination.
The two important discrepancies between the two accounts are: (1) Judas threw the money down in the Temple and the priests bought the field of blood, OR Judas, no doubt pleased by his sudden wealth, went himself and bought the field of blood (and was clearly not suicidal); and (2) Judas committed suicide, OR Judas fell down and died (by misadventure?). Various attempts to resolve one discrepancy by means of semantics still fail to resolve the other, and it is only if both discrepancies are truly resolved that we can say that both New Testaments passages are historical.
Matthew's account has more parallels to various Old Testament passages, so it is only in Matthew's account that we learn that Judas received thirty pieces of silver. John Shelby Spong, author of Jesus for the Nonreligious, points out that Judas is a variant of Judah, and that in Genesis 37:26-28, it was Judah who sought money and received 20 pieces of silver; in Zechariah 11:12-13 the king was betrayed for 30 pieces of silver, which he hurled back into the temple just as Judas did in Matthew; in 2 Samuel 17:23 Ahithophel hanged himself when his betrayal of King David was discovered, just as Judas did in Matthew as an act of repentance.
The author of Acts does not let Judas off the hook by repenting, so Judas has all this money and uses it as he would have intended to do, buying a field, but is not allowed to enjoy his sudden wealth. No sooner are we told of his purchase of the field of blood, than we are told he suffered the most satisfyingly disgusting death possible, with his bowels gushing out. This brings to mind Acts 12:23, where Herod died a somewhat similar and equally disgusting death.
This seems a clear contradiction in the New Testament. What is going on here?
A clear contradiction does exist, to such an extent that the two accounts can not be reconciled. This means that at least one account can not be historically true, but it is also possible that neither account is entirely true.
Matthew's account relies too much on the Old Testament to be plausible and so should be rejected as being a creation of the evangelist. The account in Acts is both biologically improbable - having Judas bowels literally gushing out after a fall - and too similar to the story of Herod's death in Acts 12:23, by the same author. This account should also be rejected, giving us a draw between the two stories.
Historically, there was no field of blood purchased either by the priests or by Judas. The name 'field of blood' is one of the few points common to the accounts in Acts and Matthew, but this comes from the Old Testament and has different connotations in each account, with Matthew suggesting it is because the field was purchased with the price of blood and Acts following it from Judas' bowels gushing out.