Germany’s top clubs had spent a record 600 million euros (USD 713mn) by the time the transfer window closed on Thursday with Bayern Munich boss Uli Hoeness wary of the spiralling prices.
Bayern set a new club and Bundesliga record when they signed French midfielder Corentin Tolisso from Lyon for 41.5mn euros in June.
The figure was later dwarfed by the 105mn euros their rivals Borussia Dortmund stand to make from selling Ousmane Dembele to Barcelona.
In turn, the Dembele fee was less than half of the world record 222mn euros Paris Saint-Germain paid the Spaniards for Neymar.
“At the moment, this is a game without limits, where only the players can win,” Hoeness told German magazine Sport Bild.
“I honestly don’t know where all this is going.
“We are at a point where we really have to be damned careful, because at some point the spectators will have had enough.
“I must honestly say that it’s time we got things back in proportion.”
Yet Bayern have splashed out in a big way to improve their squad in the bid to win a sixth straight German league title.
Burly Germany defender Niklas Suele was also signed from Hoffenheim for 20mn while Kingsley Coman’s switch from Juventus was made permanent after a loan spell for 21mn.
Around the league, Bayern’s rivals have also dipped into their pockets to sign new talent.
Dortmund swiftly spent some of the money they made on Dembele, who only cost them just 15mn a year ago.
Just before the transfer window closed in Germany at 1800 (1600 GMT) they signed 17-year-old Jadon Sancho from Manchester City for around eight million euros.
“We are pleased that Jadon, who is currently one of the biggest talents in European football, wanted to and will play for Borussia Dortmund,” said director Michael Zorc.
The winger has come to Germany seeking regular first-team action and could prove to be the next Dembele.
Dortmund had already signed Ukraine winger Andriy Yarmolenko from Dynamo Kiev, in a deal reportedly worth up to 30mn, and Germany Under-21 right-back Jeremy Toljan from Hoffenheim.
In the pick of the other signings, Cologne spent 17mn to replace China-bound striker Anthony Modeste with Jhon Cordoba from Mainz, but the Colombian has so far struggled.
Bayer Leverkusen splashed out a combined 36.5mn for teenage Olympiakos defender Panagiotis Retsos, 19, and Argentinian striker Lucas Alario, 24, from River Plate.
Retsos cost 17.5mn, while Alario, who still needs clearance to join Leverkusen from the Argentinian football association, cost 19mn to replace Javier Hernandez, who is now at West Ham.
Leverkusen had fallen offside with Plate for putting Alario through a medical examination without his club’s consent.
Borussia Moenchengladbach spent 17mn on World Cup-winner Matthias Ginter from Dortmund.
Hertha Berlin strengthened their attack by forking out 8.5mn on Davie Selke from RB Leipzig, even though he is currently injured.
However, the spending of the 18 clubs in Germany’s top flight is modest compared to their rivals.
The English Premier league reportedly spent 1.3 billion euros, Italy’s Serie A teams (around 800mn) and France’s Ligue 1 (around 650mn) all paid out more.