2: Peter Schmeichel
Arguably United's greatest ever 'keeper, Schmeichel was purchased in 1991 for around £505,000.
The Great Dane became an icon at Old Trafford and was instrumental in the success United experienced in the 90's.
Until the arrival of Edwin van der Sar, Ferguson never really managed to replace Schmeichel between the sticks, and United suffered for it as a result.
Schmeichel is lauded as being one of the greatest goalkeepers in the history of the game, and his starfish technique is heralded as being an evolution in modern 'keeping.
Half a million pound for countless game-winning saves? A true great.