The transfer window is a crucial period for football clubs to strengthen their squads for the upcoming season. Some spend millions to land their dream targets while a few others go for players on a free transfer.
There have been instances in history when players who signed for free made more of an impact than the club's costliest purchase. This summer saw some high-profile free transfer signings. Let's look at a team built with only those players who moved on a free transfer this summer.
Gianluigi Donnarumma (AC Milan to PSG)
From making a senior debut at the age of 16, Gianluigi Donnarumma has never looked back. He has made over 250 senior appearances for AC Milan and was named the best Serie A goalkeeper last season.
Thanks to his exploits under the bars, AC Milan qualified for the Champions League for the first time since 2014 while his Euro heroics took his stature to a whole new level. The 22-year-old was rock solid between the posts and helped Italy win the European Championship.
With Donnarumma's market value being around €62m, it was nothing short of a coup by PSG to sign a player of such stature for free.
Center-back: Sergio Ramos (Real Madrid to PSG)
After being synonymous with Real Madrid for 16 years, it was a shame that Real Madrid did not want to hold on to their captain. A warrior on the field, Sergio Ramos has won everything a footballer could want to win.
Arguably the best defender of his generation, he has not shown any signs of slowing down despite turning 34. He has five La Liga and four Champions League titles, four Club World Cups, two Euros, and a FIFA World Cup to his name.
Ramos has been named to the FIFPro World11 11 times - a record for a defender. PSG offered him the contract he demanded from Real Madrid and they will be hoping he brings them the Champions League trophy that's eluded them.
Center-back: Eric Garcia (Manchester City to Barcelona)
Eric Garcia began his football career at Barcelona's famous La Masia academy. For the club to sign him back is a happy homecoming for the 20-year-old Spaniard.
He was part of the star-studded Manchester City squad that has dominated Premier League football for nearly a half-decade. Despite his quality, however, intense competition within the team reduced his regular game time.
Garcia stands to be an asset to Barcelona over the next decade. In the post-Messi era, he could prove instrumental in bringing Blaugrana back to their glory days.
Left-back: David Alaba (Bayern Munich to Real Madrid)
After more than a decade with German giants Bayern Munich, David Alaba decided to take on a new challenge. He moved to Real Madrid after winning everything that was on offer in Germany. The 29-year-old played a big part in Bayern winning the sextuple last year.
Los Blancos' defense will feel the absence of Raphael Varane and Ramos, and it will fall to Alaba to fill that void this season. Fittingly, the Austrian has inherited the number four shirt at Real Madrid.
Right-back: Elseid Hysaj (Napoli to Lazio)
Elseid Hysaj moved to Lazio after his contract with Napoli expired this summer. The Albanian is an attacking full-back who can play on either side of the pitch. He was Maurizio Sarri's go-to man during the Italian coach's stint at Napoli.
At just 27, Hysaj still has a lot of football left in him and Lazio will be expecting him, under Sarri, to turn up for their side this season.