- Transfer fees and buyout clauses have reached new heights, but these stars could potentially be had for absolutely nothing at the end of the European season.
Amid the lucrativeness of the modern day transfer market, it sometimes goes under the radar that there can be some hidden gems scattered across the free agent market.
Free agents usually come about when a player is no longer wanted at a club, or in the case of this article, the players are very highly regarded and are seeking pastures new for financial or footballing reasons.
Let's take a look at a starting XI of star players who may be up for grabs next summer:
GK. Gianluigi Buffon, Juventus
The veteran goalkeeper is entering the last year of his contract at Juventus, and has previously stated that he is '99.9%' certain on his retirement following next summer's World Cup in Russia.
The 39-year-old is a legend in Turin, having played for the Old Lady since 2001, and has made over 490 appearances for the Serie A club.
It is unlikely that Buffon will join another club once his contract is up, but at the moment, there remains a 0.1% chance that the Italian's services will be available next summer.
RB. Juanfran, Atletico Madrid
The 32-year-old's six year spell at Atletico looks to be coming to an end, as he only has one year remaining on his contract at the Wanda Metropolitano.
The Real Madrid academy graduate has been a loyal servant in the red and white of Real's rivals, making over 200 appearances and scoring three goals.
Juanfran still has many years of top-flight football in him, and may prove to be a useful asset to any clubs scouring the free agent market.
CB. Giorgio Chiellini, Juventus
Chiellini is widely regarded as one of the best defenders in world football, having been named by The Guardian as the 50th best player in the world, as well as the seventh best player in Europe by Bloomberg.
At 33 years of age, the 92-capped Italy international's years at the top level may be running out, but he would still prove to be an exceptional defensive asset for most teams in Europe for the next few years at least.
LB. Daley Blind, Manchester United
Manchester United's Dutch utility man is out of contact next summer, an issue that Jose Mourinho will surely look to amend given Blind's versatility, as he can operate in midfield, left back and center back.
The 27-year-old is a dependable member of the United squad, and if he fails to renew terms at Old Trafford, he will make for a valuable asset elsewhere.
CDM. Emre Can, Liverpool
Liverpool have desperately been trying to tie the German international down to new terms for some time, although they find themselves at an impasse with the midfielder.
The 23-year-old is blossoming into a fine player under Jurgen Klopp's tutelage, but has been sounded out by Juventus as a potential new arrival next summer.
The Merseyside club's fears will be eased slightly by the arrival of Naby Keita next summer, although they will hope to keep hold of Can having developed him into an excellent player.
RM. Arjen Robben, Bayern Munich
The legendary winger, most commonly known for his unerring ability to cut in from the right and score with his left foot, finds himself out of contract with the Bundesliga champions as of next summer.
At 33 years of age, his abilities may not be so effective anymore, but you would surely think it is too early for his career to dwindle into oblivion in the MLS or China.
CM. Leon Goretzka, Schalke
The coveted 22-year-old superstar is struggling to agree terms on a new deal at Schalke, despite the Bundesliga side reportedly offering the prodigy a rumored £190k per week.
The likes of Bayern Munich and Arsenal have been keeping close tabs on Goretzka's situation, and after starring for his current side for many years, the midfielder may be looking for a new challenge away from the Veltins Arena.
CM. Andres Iniesta, Barcelona
It is almost inconceivable to think that Andres Iniesta may play for another team than Barcelona for the remainder of his incredible career, but after the Spaniard's recent words, it may become more real than you'd think.
The 33-year-old recently stated that he had been 'thinking about his future when before he wasn't', and has revealed that he feels he isn't getting the respect from Barcelona that he has become so accustomed to since joining the club as a teenager.
Iniesta has said he would never compete against his beloved Blaugrana, but don't rule out a move to the MLS, China or another league just yet.
LM. Alexis Sanchez, Arsenal
After failing to cash in on him this summer, Arsenal now find themselves with a want-away star player entering the final year of his contract.
Manchester City and other clubs are still keen on the Chilean in the January window, although Arsenal would be obliged to accept a significantly lower fee than expected, or risk losing Sanchez on a free next year.
The 28-year-old is a model professional and has simply put his head down and continued performing, although it is no secret that he wouldn't be adverse to a move away from the Emirates.
CAM. Mesut Ozil, Arsenal
The thought of losing both Alexis Sanchez and Mesut Ozil next summer is almost unthinkable for Arsenal fans, but it is looking more and more likely by the day.
The German international has failed to live up to his reputation as a world class performer since swapping Madrid for London, and has come under criticism for his lackluster performers.
Arsenal face the extremely real possibility of losing the pair they spent a combined £75m on for nothing, unless they tie them down quickly.
F. Lionel Messi, Barcelona
Yes, it is unlikely, but it remains a possibility. The Argentinian sensation is yet to put pen to paper on a new deal at the Nou Camp–despite the claims of the club president that his father's signature has been received and is ample–and has reportedly been left dissatisfied by the club's transfer dealings in recent years.
Nonetheless, the 30-year-old has spent the whole of his illustrious career in Catalonia, and it is difficult to envisage the four time Ballon d'Or winner plying his trade elsewhere, but at this moment in time, it remains a possibility.