Ronny Deila added two more loan players to his Celtic squad then revealed the frustrations and problems behind arranging permanent deals.
Belgian defender Jason Denayer, 19, arrived on a season-long loan from Manchester City on Monday as did Aston Villa's Bulgarian international winger Aleksandar Tonev.
Aside from snapping up out-of-contract keeper Craig Gordon, Deila's only other signing this summer has been forward Jo Inge Berget on a loan deal from Cardiff City.
The Scottish champions are cash rich following the sale of England international keeper Fraser Forster to Southampton for a reported fee of £10 million at the weekend but Deila, looking forward to Celtic's Scottish Premiership opener against St Johnstone at McDiarmid Park on Wednesday night, insists it is not so easy to buy players.
"There is money available and when I feel it is right to use it, I will use it," said Deila, who revealed he had missed out on Nancy attacking midfielder Jeff Louis who opted to sign for Standard Liege even though a fee had been agreed between the two clubs.
"I have money to spend and that is the most important thing.
"But if we buy a player for £10 million what do you think the salary of that player will be? It will be five or six times more than you get at Celtic.
"If we pay that, what will happen to the other players? You have to see the big picture. It is not about the fee, it is about the salaries.
"The money from television in the English Premiership is huge.
"Celtic is unbelievably huge but the money (here) is not so huge.
"It has to be driven in a good way and Celtic have done that for many years and will continue to do so
"But if the right player is available then there is money there."
The Norwegian, though, declared himself pleased with his two latest recruits.
"Jason is a talented and gifted player and he will make us better," he said. "Tonev, we have been watching for a long time. He didn't make a real breakthrough at Aston Villa but he has the qualities that we are looking for, a quick player who is two footed and with confidence and time he will get back to the level he was at with Lech Poznan."