AN expensive transfer does not always guarantee success.
As the current window draws to a close, clubs are desperate to add that special someone and plenty of money is sure to be splashed out.
However, when you fork out for a player who might be able to give you a boost there is always a risk that they won’t quite perform as expected.
Angel Di Maria, for example, didn’t exactly set the world alight during his spell at Old Trafford.
And this got us thinking – which current players at each Premier League club could be considered their best signing?
Additionally, where would they rank in a list of best signings across the entire league?
Here, talkSPORT have picked out the best signing at each Premier League club – that are still a part of the team – and ranked them in order of least impressive to most impressive.
20. Ciaran Clark (Newcastle United)
The Irish defender credits Magpies boss Rafael Benitez with changing his life, as he shone in defence during Newcastle’s promotion campaign.
Clark always had promise at Aston Villa but was never really able to make the grade on a consistent basis.
However, in the current Newcastle setup he has emerged as their most reliable defender.
19. Anthony Knockaert (Brighton)
The French winger played a major role in helping Brighton to Premier League promotion as he grabbed 15 Championship goals last season.
The former Leicester man signed for the Seagulls in January 2016 from Standard Liege and has proved his quality in the second tier.
However, Knockaert was unable to showcase his talents in the top tier with the Foxes and time will tell if he can prove his class among the elite.
18. Alfie Mawson (Swansea City)
As Swansea were floundering last season Gylfi Sigurdsson was undoubtedly the key man that helped save them from relegation – but he’s gone now.
However, another pivotal individual was defender Alfie Mawson who helped shore up a defence that was leaking goals left, right and centre.
Considering it was the 23-year-old’s debut Premier League campaign makes it all the more impressive, following his arrival last summer from Barnsley.
Mawson could grow into a highly competent top-level defender relatively soon.
17. Troy Deeney (Watford)
The Hornets’ club captain may not be getting the regular starts anymore but considering what Deeney has given the club he has proven a great signing.
Watford signed the forward from Walsall in 2010 for an initial fee of £250,000 rising up to £500,000 and, after an initial shaky start, his goalscoring helped the side gain promotion in 2015.
Deeney remained impressive in the Premier League but has only come on once as a substitute under new manager Marco Silva.
16. Chris Brunt (West Brom)
Jonny Evans is a viable contender but we have opted for Brunt because of his sheer longevity at the Baggies.
Boasting one of the better left foots around and, whether he’s playing at left-back or in midfield, the Northern Irishman has been a key man for West Brom since he signed from Sheffield Wednesday in 2007.
Now 32 his influence may be reduced slightly – particularly with Kieran Gibbs supposedly incoming – but Brunt will remain a reliable individual for Tony Pulis.
15. Aaron Mooy (Huddersfield Town)
The 26-year-old Australian midfielder was outstanding during his loan spell with the Terriers as they defied the odds to get promoted to the Premier League via the play-offs.
Manager David Wagner was certain the club wouldn’t have been able to get their hands permanently on Mooy, had they not been in the top flight, but Huddersfield now have a tremendous talent.
His quality goal against Newcastle could just be the start.
14. Wilfried Zaha (Crystal Palace)
A Crystal Palace youth product who didn’t quite make the grade at Manchester United, Zaha is firing again after he returned to the Eagles permanently in 2015.
The confidence has returned to the winger’s game and he was named the club’s player of the year last season as his skillful play helped stave off relegation.
He, and the rest of his teammates, are still waiting to kick into gear under Frank de Boer’s management mind.
13. Ryan Bertrand (Southampton)
After numerous loan spells while on Chelsea’s books, Bertrand finally found a home at Southampton.
He joined on loan in 2014 before completing a permanent move the following year and has established himself as one of the league’s best left-backs.
Southampton have recruited a number of quality players over the years but most of them have quickly moved on. However, Bertrand appears settled as part of the Saints back line.
12. Josh King (Bournemouth)
The Norwegian forward signed for Bournemouth ahead of their debut Premier League campaign on a free transfer from Blackburn Rovers.
The striker has progressed incredibly under the management of Eddie Howe and has added goals to his game – of his 33 career goals he has scored 23 of them for the Cherries over the last two seasons.
King has risen to become a crucial component in Bournemouth’s team and, considering he was free, he can be considered a top signing.
11. Manuel Lanzini (West Ham United)
Despite West Ham’s current problems they do possess a jewel in midfield in Manuel Lanzini – coincidentally the Argentinean’s nickname.
After coming through the ranks at River Plate, Lanzini then moved to Al Jazira in Abu Dhabi before signing for West Ham initially on a season-long loan.
Lanzini showcased his talents in his first year, convincing West Ham to sign him permanently the following summer for around £9.4million – a phenomenally low fee considering the modern day market.
In all of West Ham’s troubles Lanzini remains the one individual who can produce that magic something.
10. Tom Heaton (Burnley)
As free transfers go the Clarets’ signing of Heaton must rank as one of the better ones.
The former Manchester United goalkeeper joined Sean Dyche’s side in 2013 after shining for Bristol City despite their relegation to League One.
Since then Heaton has risen to club captain, was highly impressive last year in the Premier League and is now a regular member of the England squad.
9. Seamus Coleman (Everton)
Despite the flurry of promising Everton signings – such as Jordan Pickford – we have gone for someone established in Coleman.
The Toffees’ right-back is currently on the sidelines following his horrendous leg break but, prior to his injury, Coleman was comfortably one of the league’s best in his position.
That is even more remarkable considering Everton signed him from Sligo Rovers for just £60,000.
Still just 28 it is hoped Coleman will make a full recovery and return to something resembling his best.
8. Jack Butland (Stoke City)
The England goalkeeper had to bide his time at Stoke, when he originally signed from Birmingham in 2013, as Asmir Begovic was established number one at the Potters.
But once Begovic moved on to Chelsea, and Butland got his chance, everyone finally got to see what the shot stopper was capable of.
A near year-long injury last season delayed his progress but he is back as Stoke’s number one stopper and is the best player in Mark Hughes’ squad.
Expect Butland to be England number one going into the World Cup too.
7. Sadio Mane (Liverpool)
Forget Philippe Coutinho, Liverpool’s reigning player of the year is more important to the club.
Last summer’s signing from Southampton showed just what he can bring to the party for Klopp’s side as his searing pace helped to open up defences in his debut campaign.
Rather alarmingly Liverpool struggled to adjust without Mane during his African Cup of Nations and injury absences.
As the Reds try to make more of an impact with Klopp at the helm Mane will be a vital individual in the near future.
6. Nemanja Matic (Manchester United)
It’s a controversial choice, yes, particularly with someone like David De Gea amongst the ranks.
But here’s the reasoning – Manchester United have been crying out for a holding midfielder for years.
Michael Carrick isn’t in a place where he can fill the role game after game so, by securing Matic, United have fixed their biggest problem.
Chelsea’s decision to sell looks all the more baffling but United have gained someone that can shield and set others free – and he’s a two-time league winner.
5. Alexis Sanchez (Arsenal)
While it looks like sulking Sanchez will be departing the Emirates very soon, no one can deny what a phenomenal signing he has been for the Gunners.
After signing from Barcelona for £31.7million in July 2014 the Chilean has showcased his skill, talent and work rate and it’s no surprise Manchester City want him desperately.
So, while he is still an Arsenal player, he remains on this list.
4. Jamie Vardy (Leicester City)
Signed for £1million from Fleetwood Town, Vardy helped Leicester to their promotion from the Championship in 2014 – and then he went and won the Premier League title with the club.
The England man was Leicester’s top scorer in their shock Premier League win and, while anything resembling that season’s success is highly unlikely, the former non-league forward still finds the back of the net often enough.
3. Dele Alli (Tottenham)
When Alli signed for Tottenham, in a £5million deal from MK Dons, few people would have expected him to make the immediate impact that he has.
Partly thanks to Mauricio Pochettino’s faith, Alli is now one of the best young talents in world football and is both a key man at club and international level.
In his time at Spurs, Alli has won back-to-back PFA Young Player of the Year titles and scored 34 goals from midfield.
All of that and he only turned 21 back in April.
2. Eden Hazard (Chelsea)
If we ignore the 2015/16 season, where the Belgian’s talents utterly deserted him, Chelsea’s number ten has shown time and again what he is capable of in a blue shirt.
A £32million signing from Lille in 2012, Hazard has helped Chelsea to two Premier League titles, one League Cup, the Europa League title and he won the 2015 PFA Player of the Year award.
He remains a key attacker at Stamford Bridge and there is still plenty to come for a man who is still only 26 years old.
1. Sergio Aguero (Manchester City)
While the striker may have been warming the bench more often than he would like in recent times you can’t deny the impact Aguero has had at Manchester City.
In 255 appearances the Argentine has plundered in 170 goals since he signed from Atletico Madrid in 2011 for £38million.
He’s a bona fide club legend and let’s not forget the incredible last minute winner that sealed City’s first Premier League title on the final day of the 2011/12 season.
Aguero has written himself into history – that’s what makes him number one.