People usually reply: in the current market.
But, the thing is, NOT all players are inflated.
Or, NOT all players are inflated equally.
For example, if 5 years ago, CR7 was worth 100M, today he is worth, let's say 200 or 250.
The same as Neymar.
So, the price for TOP PLAYERS have doubled or tripled.
So, yes, we have an inflation here.
Also, players whom TOP teams are interested in like Bellerin, Semedo, Keita, Seri, Verratti=are inflated also.
Players like Bellerin and Semedo were worth 15-25M a few years ago.
Today they are worth 50-60M.
On the other hand, crap or average players in whom no one is interested=are not inflated.
Or, in best case, their price is only 1-2 Millions higher than a few years ago.
So, if Neymar's price jumped from 80-100 Millions to 200-250 Millions, on the other hand, a price of Douglas, Montoya, Bojan Krkic, Tello and other guys is NOT inflated.
No one wanted Tello, Montoya or Douglas 5 years ago. And the same is today.
So, if Tello was worth 8-10 Millions a few years ago, his price HASN'T jumped to 20-25, because of "current market".
Tello was an average player whom no one wanted both 3 years ago and today.
His price was 8-10M both 5 years ago and today.
So, again, people shouldn't reply: if Semedo is worth 50M, then Rafinha is worth 30M.
Well, he isn't.
Supply and demand.
TOP teams are interested in Semedo (Barca, Man Utd and similar) and we are willing to pay (or to overpay) 50-60 Millions.
On the other hand, who on Earth is interested in Rafinha?
Real, Psg, Man Utd, City?
He is not good enough for top teams.
And he is not good enough for TOP and RICH teams.
He is good enough for 2nd or 3rd tier teams who don't have money and who usually buy players worth 1-10 Millions (like Celta, Valencia and similar).
So, again, Rafinha can't be worth 30 Millions since teams who are able to spend 30M for a midfielder are not interested in Rafinha (Real, Bayern, City, Liverpool).
And teams who ARE interested in him can spend 10 to 15M max.
So, a price which we can get for Rafinha is 10-15M, and NOT 30M.
The same applies for Arda and other guys.
Who on Earth will buy 30 years old out of form and declining Arda and pay his insane wages?
If we get 15M for him, that will be the biggest gift in the world.
In short: "current market" isn't inflating prices of every single player in the world, but mostly prices of players in whom top10 and 2nd tier rich European teams are interested in.