Judge James Adkin told the two teenagers: “You were both active class A drug dealers.”
He added Rowsell acted out of “simple greed for money” that was “greater than your concern for any customer”.
He said: “Rowsell was in business for himself. He was in it for money and status.
“The business had been going on for months. That night alone he sold 35 and intended to sell many more.
“He was selling to children, targeting youngsters at a nightclub where no alcohol was available, it was purely for children and was a dry evening.”
He added: “Lucy Hill died because you sold her drugs, you sold her two tablets, despite the fact that you were concerned about the dosage.
“It seems to me you were simply greedy, and your greed for money was greater than your concern for any customer.”