Who is the best value signing in Premier League history? [See top 10]

In the summer of 2012, European champions Chelsea were in the midst of a busy transfer window, signing the likes of Eden Hazard, Oscar and Victor Moses.

While promising youngsters Kevin De Bruyne and Romelu Lukaku had returned to Stamford Bridge following successful loan spells and were hoping to get their chance in the first team.

Meanwhile, as the window neared its end the Blues swooped for the 22-year-old Spaniard Cesar Azpilicueta in a move that was deemed to be nothing more than an addendum to the statement-making business they'd already conducted.

In hindsight, the hype around Hazard was more than justified and in today's ludicrous financial climate his £32m fee is cheap. Still, Azpilicueta's purchase for just £7m is even more noteworthy.

Last week the Spanish defender departed the club after 11 years, 508 appearances and seven major trophies that made him a legend and one of the best value-for-money purchases during the Premier League era.

But how do you even go about accurately judging the value of a transfer? Here at Mail Sport we've set ourselves that inevitable task of ranking the deals that look extraordinary after the fact.

Team and individual success certainly comes into the equation, as does club tenure. Players aren't ranked specifically based on their ability or career achievements, instead we've looked at those who have performed wonders for clubs that have got them on the cheap.

We're keeping free transfers to a minimum - because they probably deserve their own list - and favouring frugal purchases.

So with all that out of the way, with Azpilicueta ranking as our No 10, here's the rest of our list.

9. Edwin van der Sar - £1.5m from Fulham in 2005

The Dutch stopper was brought in as a short term solution for United's persistent troubles in goal. The 34-year-old penned a two-year deal, originally planned to ready the way for promising youngster Tim Howard following the departure of Roy Carroll.

Van der Sar ended up staying for six seasons in which he won four league titles, two League Cups and the Champions League by forming one of the most formidable defensive units behind Rio Ferdinand and Nemanja Vidic.

United's run of 14 consecutive clean sheets, achieved in the 2008-09 season, is a record which still stands today.

The Dutchman worryingly suffered a brain haemorrhage while on holiday in Croatia last week.

But in an update on his condition on behalf of his wife, Annemarie, Ajax revealed on Tuesday night that while he's 'still in the intensive care unit', he is 'not in life threatening danger'.

Edwin van der Sar joined Man United when he was 34-years-old and spent six years at the club

8. James Milner - Free signing in 2015

Coming off the back of a bruising sixth-placed finish, the club recruited Christian Benteke, Roberto Firmino, Nathaniel Clyne, Danny Ings, Joe Gomez and Milner.

It's fair to say some of the deals worked out better than others, but at least two of those names played pivotal roles in the success the club would have under Jurgen Klopp, who was appointed later that year.

Under the German's tutelage, Milner became Liverpool's 'Mr Dependable', playing every minute in whatever position was required and dispatching penalties before the arrival of Mohammed Salah.

The 37-year-old joined Brighton this summer after collecting a League Cup, FA Cup, Premier League and Champions League with the Reds.

James Milner is currently third in the Premier League's all-time appearances makers with 619

7. Andrew Robertson - £8m from Hull City in 2017

Only one of those players can boast a more successful six years since, and he set Man City back £50m.

Robertson meanwhile has grown from strength to strength after arriving from relegated Hull City, forming half of one of the most devastating full-back partnerships with Trent Alexander-Arnold.

The Scottish skipper's list of honours at Anfield are the same as Milner's above, but at 29-year-old he's got plenty of time to add to his tally.
Andrew Robertson has racked up 63 assists for the Reds in 267 appearances since joining

6. Patrick Vieira - £3.5m from AC Milan in 1996

'He was in Holland, he was there to sign but I knew his agents,' Wenger explained to Arsenal.com. 'I spoke to Patrick and said, 'Please, stop. Come to Arsenal.'

Vieira quickly established himself as a key cog in the French manager's all conquering side and famously captained the roster as they achieved the remarkable feat of going the entire 2003-04 season unbeaten.

In nine years at the club, Vieira played 406 times and scored 33 goals, inheriting the captain's armband from Tony Adams in 2002.

He won three Premier League titles and the FA Cup four times, leaving a hole that has never quite been filled after he left for Juventus in 2005.

Vieira captained a star-studded Arsenal who went the 2003-04 season unbeaten

5. Vincent Kompany - £6m from Hamburg in 2008

In hindsight, it ushered in a period of dominance for the Manchester side. But the key to their improvement was not found in the tricky Brazilian, who infamously thought he was signing for Chelsea, but with a largely understated Belgian defender.

in 2010-11, Kompany helped guide the Citizens into the top four, racking up a half-century of appearances along the way as Roberto Mancini's side finally emerged as contenders.

A year later he captained the side as they finally achieved their aim of winning of the Premier League. And though Sergio Aguero's strike on the final day has rightly been immortalised, Kompany winner against Man United two games prior was just as important.

Vincent Kompany played 360 games for Manchester City during his 11-year Etihad career

4. Jamie Vardy - £1m from Fleetwood Town in 2012

The Foxes put down £1m to sign the then 25-year-old, who had terrorised National League defenders and scored 34 goals the season prior.

Looking back at what Vardy has achieved at club and international level, it's clear he really had no business playing in the fifth tier.

Despite Leicester's fairytale few years coming to an abrupt end last season, nothing could take the shine off the Premier League, FA Cup and golden boot the Sheffield native has won while in the east Midlands.

Vardy is the Premier League's 15th highest scorer, notching up 136 goals in the competition

3. Nemanja Vidic  - £7m from Spartak Moscow in 2005

The Serbian anchored a fearsome centre-back partnership with Ferdinand and captained the Red Devils as they asserted themselves as the dominant force in England once again.

Globally they were second only to Pep Guardiola's Barcelona, who bested them in two Champions League finals.

Still, while at Old Trafford, Vidic claimed five Premier League titles, three FA Cups and the Champions League in 2008. His £7m signing represented unbelievable value for a modern icon who went on to make 300 appearances for the club.

Nemanja Vidic joined Man United during the winter transfer window of the 2005-06 season

2.  Sol Campbell - Free signing in 2001

However, Campbell opted to join Arsene Wenger's exciting Gunners project where he established himself as one of the best centre-backs of his generation.

Campbell was certainly vindicated in his decision, as were Arsenal who go their hands on a fine defender who would spend five years at the club.

Two league titles and three FA Cups is pretty good going for a free transfer.

Campbell opened the scoring for Arsenal in a 2006 Champions League final loss to Barcelona

1. Eric Cantona - £1.2m from Leeds in 1992

A talismanic figure, championed above all by the manager, who sets new expectations for what is possible thanks to their startling displays on the pitch.

Put simply, for United to have unearthed such a pivotal character to their recent history from a rival and for the cost of £1.2m in extraordinary.

Cantona wasn't even in the top five most expensive transfers that summer but went on to win four league titles and two FA Cups during his half decade in Manchester.
Cantona's purchase from rivals and First Division champions Leeds paved the way for success