Earlier in the transfer window, Manchester United were rumoured to have bid £30 million for 16-year-old Jude Bellingham.

Thirty million pounds for a fifteen-year-old.

Crazy.

It would, of course, be a world-record fee for a player of that age.

It got us thinking. Who is the most expensive player at every age?

Well, using data from TotallyMoney.com, we've discovered the most expensive transfer featuring a player of every age from 13-40.

Let's take a look:

13-years-old | Finley Burns | Southend to Manchester City | £175,000

Three years ago, Man City spent a record fee for 13-year-old Burns, who was also being eyed by Liverpool, Chelsea and Arsenal. Now 16, the defender has been playing regularly for City Under 18s.

14-years-old | Sheyi Ojo | MK Dons to Liverpool | £2 million

Back in 2011, Liverpool beat off competition from a host of Europe's top clubs to sign Ojo from MK Dons. But the winger, who has played 13 times for Liverpool’s first-team, is now in his sixth loan spell away from the club at Rangers. At 22, it seems Ojo is failing to fulfil the potential he showed as a 14-year-old.

15-years-old | Raheem Sterling | QPR to Liverpool | £5 million

Liverpool strike again. This time, it was money very well spent. Only two years after signing, Sterling was making his first-team debut at Liverpool and went on to play 129 times for the club, scoring 23 goals. During the 2013/14 campaign, Sterling was brilliant playing in-behind Luis Suarez and Daniel Sturridge. But in 2015, he left unceremoniously to Manchester City for £49 million, where he’s taken his career to the next level under Pep Guardiola.

16-years-old | Pietro Pellegri | Genoa to Monaco | £18.8 million

Pellegri was the joint-youngest player to appear in Serie A when he made his debut for Genoa, aged 15 years and 280 days. He impressed so much during the first half of the 2017/18 season that Monaco snapped him up. He’s broken Kylian Mbappe’s record of the youngest league player in the club's history but has only appeared six times since signing for the club in January 2018.

17-years-old | Alexandre Pato | Internacional to AC Milan | £21.6 million

Pato was impressing in Brazil when he caught the attention of AC Milan in 2007. He spent six seasons at the San Siro, scoring 63 goals in 150 matches. But injuries have spoiled his career somewhat. The 30-year-old now finds himself at Sao Paulo.

18-years-old | Vinicius Junior | Flamengo to Real Madrid | £40.5 million
= 18-years-old | Rodrygo | Santos to Real Madrid | £40.5 million

Real Madrid have made two pretty expensive signings for 18-years-olds recently. The pair of Brazilian 19-year-olds look like potential superstars and have already represented their country as well as impress in Real’s first-team. £40.5 million could look very cheap in a few years’ time.

19-years-old | Kylian Mbappe | Monaco to PSG | £121.5 million

Talking about transfer fees that could look very cheap in a few years’ time…

Mbappe is currently the second most-expensive player in the history of football but he’s a superstar in the making. In fact, he’s already a superstar and is surely a future Ballon d’Or winner. Since moving to PSG, the 21-year-old has scored 81 goals in 110 matches.

20-years-old | Ousmane Dembele | Borussia Dortmund to Barcelona | £112.5 million

Dembele’s big-money move to Barcelona hasn’t exactly gone to plan. The Frenchman initially appeared to be ill-disciplined off-the-pitch and has only managed 19 goals in 74 matches since arriving at the Camp Nou.

21-years-old | Neymar | Santos to Barcelona | £79.38 million

Neymar was running rings around Brazil’s Serie A with Santos when Barcelona splashed almost £80 million on a 21-year-old. He repaid the transfer fee with 105 goals in 186 matches before moving to Paris Saint-Germain for a world-record fee. More on that later…

22-years-old | Frankie de Jong | Ajax to Barcelona | £67.5 million

De Jong has the potential to be the best midfielder in world football so Barcelona’s £67.5 million fee spent on him is seen as pretty good business.

23-years-old | Paul Pogba | Juventus to Manchester United | £94.5 million

It was a world-record fee at the time but Pogba hasn’t exactly repaid it. On his day, one of the best midfielders in the world but he hasn’t had his day too often at Old Trafford recently.

24-years-old | Gareth Bale | Tottenham to Real Madrid | £90.9 million

Another transfer that broke the world-record fee at the time. Back in 2013, Real Madrid spent £90 million on the Welshman. Despite what the Madrid media and fans try to say, he’s repaid that with 105 goals and four Champions League finals - scoring goals in two of those finals.

25-years-old | Neymar | Barcelona to PSG | £199.8 million

The most expensive transfer in the history of football. Has it been worth it? Sixty-four goals in 74 matches suggest yes. All of his injuries and controversies suggest otherwise.

26-years-old | Harry Maguire | Leicester to Manchester United | £78.3 million

No, really. Maguire’s fee edges out Virgil van Dijk, who is the second most expensive 26-year-old ever. He’s already established himself as club captain but is he worth anywhere near £78 million? No.

27-years-old | Luis Suarez | Liverpool to Barcelona | £73.55 million

Barcelona spent a massive amount of Suarez despite him biting Giorgio Chiellini at the 2014 World Cup. The biting has stopped but the goals haven’t. 191 in 270 matches has established Suarez as one of the best striker’s in the club’s history.

28-years-old | Antoine Griezmann | Atletico Madrid to Barcelona | £108 million

Suarez was joined by Griezmann this summer after his controversial move from Atletico Madrid. The 28-year-old made a slow start to his Camp Nou career but has scored 11 goals in 27 appearances to date.

29-years-old | Zinedine Zidane | Juventus to Real Madrid | £69.75 million

Spending £70 million on a 29-year-old is a risk - especially back in 2001. But it was an incredible decision. Zizou graced the Bernabeu with his magic for five seasons and will always be remembered for his incredible volley in the 2002 Champions League final against Bayer Leverkusen.

30-years-old | Leonardo Bonucci | Juventus to AC Milan | £37.8 million

Well, this went well…

Bonucci’s move to Milan was a disaster, lasting just one season before a return to Juventus in a swap-deal with Mattia Caldara.

31-years-old | Gabriel Batistuta | Fiorentina to Roma | £32.54 million

The legendary ‘Batigol’ scored more than 200 goals for Fiorentina before making a move to Roma late in his career. His debut season following his £32 million move resulted in 20 goals in 28 Serie A matches.

32-years-old | Fernando Llorente | Swansea to Tottenham | £13.59 million

Llorente spent a lot of his career at Athletic Bilbao before joining Juventus and Sevilla. His one and only season at Swansea saw him score 15 goals in the Premier League, which encouraged Tottenham to splash the cash on the veteran. He was very much ‘Plan B’ and used as a target man substitute, playing second-fiddle to Harry Kane. He will always be remembered by Spurs fans for scoring THAT goal against Manchester City in the Champions League to get them through to the semi-final. The 34-year-old is now at Napoli.

33-years-old | Cristiano Ronaldo | Real Madrid to Juventus | £105.3 million

You shouldn’t really be spending more than £100 million on a 33-year-old but when it’s Ronaldo, it’s understandable. Just the 47 goals in 68 appearances - including 16 in 17 Serie A games this season - since his arrival. He may be slowing down but he’s still incredible.

34-years-old | Lilian Thuram | Juventus to Barcelona | £4.5 million

After Juventus’ relegation after the ‘calciopoli scandal', Barcelona raided them for legendary right-back Lillian Thuram. He wasn’t always a regular at the Camp Nou but played out his final two seasons.

35-years-old | Jose Luis Chilavert | Velez Sarsfield to RC Strasbourg | £4.77 million

It’s easy to forget that Chilavert was actually a legendary goalkeeper, having represented Paraguay 74 times. But he was also a fantastic free-kick taker, scoring 67 goals during his career.

36-years-old | Naldo | Schalke to AS Monaco | £1.8 million

Perhaps the worst £1.8 million ever spent in football. Naldo got sent off in his first two matches and only played nine matches in total before he had his contract terminated.

37-years-old | Brad Friedel | Blackburn to Aston Villa | £2.25 million

Friedel hadn’t missed a single match in the last four Premier League seasons when he joined Aston Villa as a 37-year-old. And during his three campaigns at Villa Park, he played every single league match meaning he went seven consecutive league seasons playing every match. There was still time for Friedel to make another move in his career, joining Spurs where he eventually missed a league match - but only in his second season there.

38-years-old | Marko Simeunovic | AEL Limassol to Interblock | £765,000

The Slovenian goalkeeper played for the likes of Olimpija Ljubljana and Maribor and represented his country 57 times.

39-years-old | Craig Brewster | Inverness to Dundee United | £340,000

The striker played for a whole host of Scottish sides and was a player-manager at Inverness when Dundee United decided to pay a world-record fee for a 39-year-old. They were getting a manager and a player in one, mind.

40-year-old | Bogdan Stelea | Unirea Urziceni to Brasov | £85,000

Who could forget when the legendary Romanian goalkeeper joined Brasov for a record fee for a 40-year-old? Errr everyone. Stelea actually played for all three major Bucharest clubs during his career but has since retired to become Romania’s assistant manager.