#4 Jermaine Pennant

Eyebrows were raised when Arsenal signed Jermaine Pennant from Notts County for £ 2 million, which was the record transfer fee for a trainee at that time. He was the youngest player to feature for the Gunners when he was given his debut against Middlesborough in the League Cup, a record surpassed by Cesc Fabregas and Jack Wilshere in the recent times.
With just 5 starts in 7 years, the winger scored just three goals that have come in a hat-trick against Southampton on his full league debut in 2003. His off-field issues, coupled with poor displays eventually lead to loan spells with Watford, Leeds United and Birmingham before signing on a permanent basis for £ 3 million.

The one-time prodigy signed for Liverpool in the summer of 2006 from Birmingham for £ 6.7 million. He spent 3 years with the Reds, featuring in 81 games and scoring 3 league goals in the process before being loaned to Portsmouth.