Admittedly Cristiano Ronaldo cost far from than any other player on this list, but considering the amazing things he achieved during his six years at United, he still proved to be unbelievable value for money. Ronaldo joined for just over £12m from Sporting Lisbon in 2003, and his Man of the Match display on his debut against Bolton Wanderers made it abundantly clear that Ferguson had a young genius on his hands. Although he blew a little hot and cold during his first two or three seasons, when he returned to Old Trafford following the 2006 World Cup, his game suddenly went up a gear. He was winning United games single-handedly at times, and his goalscoring, creativity and pace made him a nightmare for any defender. The Portuguese superstar scored 91 goals in total over the next three years, culminating in United winning the Premier League three times in a row. 2007/08 was probably his finest season, as he scored 42 times in just 49 matches. He left for Real Madrid in 2009, and the world-record fee of £80m meant United had made almost a £70m profit on the player. The 29-year-old has got even better during his five years in Spain, and is now undoubtedly one of the greatest players in the history of the game.
