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."
Denayer goes into the squad for the trip to Perth and he claimed he would be ready, if required, for the Champions League play-off first-leg match against Maribor next week.
''I am sure I can play,'' he said. ''I thought about it before I came and if I wasn't ready to come to play then I wouldn't have come.''
However, he was not keen to have too many comparisons made with City and Belgium skipper Vincent Kompany.
He said: "I have learned a lot from him because he is a good guy off the pitch. He talks a lot with me so he helps me a lot.
"He is Belgian like me, a defender like me, Congolese (background) like me, but I don't want to be the same as Kompany.
"Maybe the same career but not the same player because I want to have my own style.
"I am fast, strong and I try to play football, not just kick the ball."
Denayer, who played against Dundee in a pre-season friendly game for City, wants to return to make his mark at the English club and is confident he will get his chance to do that by impressing at Parkhead.
"I can't say what will happen in the future but I want to show that I can play in the first team for City,'' he said.
"I asked to go on loan and Celtic were the club who gave me the most assurances to play.
"When I spoke with the manager he told me he was going to give me my chance, so when I get my chance it is up to me."