Ole Gunnar Solskjaer says "not everyone can spend millions and millions" as he seemingly cast doubt on Manchester United's plans to further strengthen their squad.
United have made one signing since finishing third in the Premier League last season, bringing in Donny van de Beek from Ajax for a fee that could rise to £39.1 million (A$70m).
Borussia Dortmund attacker Jadon Sancho is widely considered to be a primary target for Solskjaer, but United have been unable to reach an agreement with the German club.
Left-backs Sergio Reguilon and Alex Telles have also been linked, though Solskjaer is adamant his side will not pay over the odds for any targets in the current market.
"We are always looking to see if there is any way possible that we can improve this squad and bring players in that will have the right level, quality, personality and fits all the criteria," he told BBC Radio Five Live.
"This summer and year has been a strange one and it is very important everyone understands this has an effect on football. Not everyone can spend millions and millions.
"It is never easy to have too many new players in the team, it takes time for players to gel into a unit.
"We have seen some clubs go for the quick fix and some have trust in the process. We have to improve and get results but adding players with different qualities than we have."
When asked how many more signings he would like to make before the transfer window closes on October 5, Solskjaer said: "I never set myself a target, like scoring 20 goals as a player.
"You just have to go day by day, making sure you develop and improve. We have a vision of where we want to get to but know so many things can come in the way. I believe in seeing how the team and club develops."
United could well go into their opening Premier League game against Crystal Palace next week with Van de Beek as their only new recruit.
Solskjaer is pleased with his side's business to date, however, with Van de Beek providing some added competition for Paul Pogba and January signing Bruno Fernandes.
"When we signed Bruno, we knew we needed that type of player," he said. "Now we have signed Donny, he is the type of player I felt we needed in the squad and the type of person that will fit the culture and the team and will improve us for next season.
"He is a versatile player, he is clever and has plenty of energy and enthusiasm. He scores goals and that is what we need to add from midfield.
"We need goals throughout the squad, we did not score enough to challenge at the top.
"On signing players, you use the people you know and trust, so I spoke to Ajax director of football Edwin van der Sar and our defender Timothy [Fosu-Mensah] before signing Donny."
United have had less than a month off since concluding their 2019-20 campaign with defeat to Sevilla in the Europa League semi-finals.
Despite finishing his first full campaign at Old Trafford trophyless, Solskjaer is happy with the progress he has made in his 21 months at the helm.
"We are looking forward to the new season, but it has come around so quickly from last season," he said. "The preparation is very different to what we normally have, and we have to take our Europa League games as pre-season.
"We are a developing team, a year or so into our rebuild. We had to make some decisions last summer and throughout the season we have seen how this team is getting better and getting used to each other.
"I'd rather be an optimist and be wrong than be a pessimist and be right. I did think we would qualify for the Champions League but I was hoping for a trophy along the way as well."