City's willingness to invest heavily in their playing squad has gained much attention in recent years.
However, Cook, who left the club in 2011, insists the Etihad Stadium outfit were relatively cautious with their dealings after Mansour completed his takeover in 2008.
"The players and agents and football clubs all think, because you've got all that money, you should pay it," said Cook.
"There's no reason why you should, just because you have.
"So we actually lost more business than we did by virtue of the fact that we wouldn't meet everyone's most ridiculous demands."
After winning the Premier League in 2012, City remain firmly in the hunt for a second title in three years ahead of this Sunday's much-anticipated meeting with leaders Liverpool at Anfield.
