Hey kiddo! So you know how Judas Iscariot was one of Jesus' 12 disciples, right? Well, the "bargain of Judas" refers to a story from the Bible where Judas agreed to betray Jesus to the authorities in exchange for some money.
Now, you might be wondering why Judas would do such a thing to his friend and teacher. Well, some people believe that he was disappointed with Jesus and wanted to force him into action. Other people think that he was motivated by greed, and just wanted some cash.
Either way, the "bargain" part of the story comes in when Judas met with the high priests of the Jewish temple and struck a deal with them. He agreed to lead them to Jesus so that they could arrest him, and in exchange they would give him 30 pieces of silver (which was a lot of money back then).
Now of course, we know that this wasn't a very nice thing for Judas to do, and it ultimately resulted in Jesus being crucified. But the "bargain of Judas" remains an important part of Christian history, and is often used to illustrate the consequences of greed and betrayal.