Aguero is set to depart the Etihad Stadium at the end of the season after City decided not to extend his 10-year stay at the club.
The Premier League leaders have been linked with a host of big names including Borussia Dortmund forward Erling Haaland, Romelu Lukaku and Harry Kane but none of them will come cheap.
According to Guardiola, the financial implications of the coronavirus pandemic means City will have to make do with what they have or promote from the club’s academy to fill Aguero’s void.
"With these prices we are not going to buy any striker. It is impossible, we cannot afford it," the Catalan coach said during a news conference on Friday.
"All clubs struggle financially, we are not an exception. We have Gabriel [Jesus], Ferran [Torres], young academy players, false nines. I don't know what will happen.
"Today there is more of a big chance we won't sign a new striker for next season."
Aguero joined Man City from Atletico Madrid in the summer of 2011 and he has become the record goalscorer for the club in that time, scoring 257 goals in 384 appearances across all competitions.
"We know how important he is in the present and past. These decisions are never easy," Guardiola added.
"I want to be clear: Maybe we'll find a new player to replace Sergio. In terms of numbers he might be replaced, but in terms of what he means to the club it is impossible.
"We have enough players in the first team, interesting players in the academy. But with the economy the way it is we're not going to sign a new striker this summer."
