Speaking ahead of Sunday's Community Shield against Manchester City, Arteta pointed to deals like Morgan Rogers' £100m-plus move as evidence of how far prices have risen, having watched Arsenal's own interest in Rogers come to nothing earlier in the window.
"Yes, it has (transfer fees surprised me)," Arteta said. "I wouldn't bet on that (such high prices) to be fair. But that's the market. There are clubs that are happy to invest or they believe that the valuations of those players are that.
"And that's fair. At the end the value of the player is what somebody can pay for you and they've done it."
Arsenal have generally avoided paying at the top end of the market this summer, with Bruno Guimarães arriving for £75m after a protracted saga representing the club's most significant outlay, alongside deals for Christos Tzolis and the permanent capture of Piero Hincapié.
The Gunners are continuing to assess options up front, with Galatasaray's Victor Osimhen and Atlético Madrid's Julián Álvarez both under consideration as the club looks to add a further attacking option before the window closes, having already missed out on Real Madrid's Vinícius Júnior earlier in the summer.
Arteta also opened the door to Ethan Nwaneri leaving the club, with the 19-year-old having spent much of the second half of last season on the bench during his loan at Marseille and recently drawing interest from clubs including Galatasaray.
"It's unquestionable the talent, the desire, the love and the passion he has for the game," Arteta said. "It's something that I've always loved about Ethan. I think he's had some great games and he's shown everybody that he has the ability to be here.
"I want him to be at the club but something that, in the medium-long term, is best for the player as well. Ethan needs to play football and if he stays here it's because we can guarantee that he can have those minutes. Otherwise it's just something that is not good for anybody I think."