Judge John Royce said Ben Hope and Jason Richards had shown no remorse for the mistaken murder of 17-year-old Aamir Siddiqi.
Prosecutors said 39-year-old Hope and 38-year-old Richards were paid 1,000 pounds ($1,600) each to kill a man who owed money to a businessman. But the pair killed Siddiqi on his doorstep instead.
Last week a jury at Swansea Crown Court found the pair guilty of Siddiqi's 2010 murder and the attempted murder of his parents.
The judge said Friday that the men had killed a "bright, gentle and courteous boy" who had a future "brimming with promise."
