Leroy Sane is an expensive purchase, but if you play your cards right and pick him up for close to his value, you're guaranteed to get a decade of quality service from the German youngster. He's 19 and already good enough for the Premier League, with a few stats teetering on the edge of double figures. A couple of years being tested at the top level will prove immeasurably helpful for his development and you'll have a superstar on your hands.