They sold him to Potiphar, the chief of Pharaoh's bodyguard in Egypt.(Genesis 37:21-28, 36; 39:1)
All of them except Benjamin collectively plotted to do something to Joseph to hurt him. Initially it was to kill him then just to throw him into the well so the brothers could be rid of him.
The account at: Genesis 37:28, says it was the Ishmaelites.
Well, honey, let me break it down for you. Joseph was sold for 20 pieces of silver because that was the going rate for a slave back in the day. His brothers saw an opportunity to make a quick buck and didn't give a second thought to betraying him. It was a shady deal, but hey, that's family for you.
Joseph's brothers sold him. Genesis 37: 25 And they sat down to eat bread: and they lifted up their eyes and looked, and, behold, a company of Ishmeelites came from Gilead with their camels bearing spicery and balm and myrrh, going to carry it down to Egypt. 26 And Judah said unto his brethren, What profit is it if we slay our brother, and conceal his blood? 27 Come, and let us sell him to the Ishmeelites, and let not our hand be upon him; for he is our brother and our flesh. And his brethren were content. 28 Then there passed by Midianites merchantmen; and they drew and lifted up Joseph out of the pit, and sold Joseph to the Ishmeelites for twenty pieces of silver: and they brought Joseph into Egypt.
Joseph used it to put Benjamin in a situation where his brothers would have to protect Benjamin or let him suffer. Since Benjamin was the now the favored son since Joseph's departure, this would show if his brothers had learned their lesson from having sold him to the Ishmaelites. Since Judah rose up and chose to take Benjamin's place as Joseph's slave (the penalty for theft), Joseph realizes that his brothers have learned their lesson.
Judah did not want Joseph to be killed and preferred selling him to the Ishmeelites. Reuben also did not want to kill Joseph. He suggested they throw him into the cistern and secretly planned to save and return him to their father later, but his brothers sold Joseph in his absence.
They came out of Jordan Ishmaelites were the descendants of Ishmael who was Abraham's son from his wife Sara's maidservant.
The Grateful Dead
It was Poitphar the captain of Pharoah's guard. Genesis 39:1 Now Joseph had been taken down to Egypt. And Potiphar, an officer of Pharaoh, captain of the guard, an Egyptian, bought him from the Ishmaelites who had taken him down there.
they sold him
No, she died soon after the birth of his younger brother Benjamin. Benjamin was alive when Joseph was sold.