Rafa Benitez says he's 'not happy' after Newcastle United missed out on several transfer targets.
The club has signed five players at a cost of just over £30million so far this summer.
And Benitez is looking to sign more players before the transfer window closes later this month.
However, Benitez was frustrated to lose out on a number of targets, including Tammy Abraham and Willy Caballero, earlier in the summer.
Speaking to Sky Sports today at the launch of the new Premier League season, United's manager said: “The story is, as I said before, we missed our targets.
“I can read our fans saying ‘we will sign a £25m striker’. Listen, we cannot.
“Sometimes they are unavailable, and if they are available, sometimes the wages are not the same, the commission is not the same and the wages are huge.
“I think we will try to do our best in our the market.
"I'm not happy, but at the same time it’s a challenge. It's very hard – the prices are crazy.
“We missed some targets at the beginning, and I think we're paying for that."
Benitez, however, admits it would be "very difficult" for him to walk away from the job – and he reiterated his commitment to the promoted club.
“No, I decided to stay," said the 57-year-old. "When I decided to stay it’s because for me it’s a challenge.
"For me, I’m not totally happy with what we did, but I will try to do my best, working very hard with people at the club to try and improve what we have at the moment.
“It’s very difficult (for me to walk away). My Chinese is not good enough.
“I try to do my best now. It has to be something you cannot control. At the moment, I'm fully committed to do the best that I can do now."
Newcastle kick off their campaign with a home game against Tottenham Hotspur on Sunday.