6) Luke Shaw (Southampton to Manchester United) - £30m

If United had broken the record transfer fee to sign a teenager when they signed Rooney in 2004, they broke it again a decade later when they signed Luke Shaw from Southampton.
Shaw was such a talented player in his youth that he was playing against players two to three years older than him. He broke into the Saints' U-18 team at the age of 15!
Arsenal, Chelsea and Manchester City had targeted the young player when he was impressing with the youth teams but then-manager Nigel Adkins shooed them all away.
when Southampton returned to the Premier League, Shaw impressed in his two seasons, picking up a Young Player of the Year nomination and earning a spot in the Team of the Year in his final season alongside teammate Lallana.
By then his stock had increased almost ten-fold and the club could not turn down United's offer to sign him for £30m.