Sam Allardyce has claimed that increased spending in the transfer market is making the job of football manager "increasingly difficult".
More than £850m has been spent by Premier League clubs in the transfer window, which ends on August 31.
Accountancy firm Deloitte has claimed that English top-flight sides are on course to surpass the record £1.165bn they spent last summer.
Allardyce resigned as Crystal Palace boss in May, citing the stresses of club coaching as a major factor.
"The difficulty for managers is the amount of money that is being spent," the 62-year-old told BBC Sport.
"The actual increase in the team is probably less than 5% and that's what you're searching for now.
"You're searching for just a small percentage and having to pay millions and in some cases hundreds of millions for that little difference."
Since announcing his hiatus, former England boss Allardyce revealed that he would be open to the prospect of a return to international management.
