Young claimed an unprecedented third Premier League player of the month title in one season when winning the December award and O'Neill joked that the achievement had added millions to his market value.
'What did I say he was worth before? Was it £75 million? Well, let's make that £82 million now,' joked O'Neill.
'Players like Ashley Young and Gabriel Agbonlahor are priceless – absolutely irreplaceable.
'I wouldn't contemplate selling off players. But then again I'm sure AC Milan would not have entertained any bid for Kaka. Now they must be entertaining it.
'But it's not going to happen here. What is going on is quite incredible and I think it will have repercussions. It's staggering.'
O'Neill is watching with interest the incredible developments at Eastlands though sounded a note of caution for those who believe that by flexing their financial muscles City are guaranteed success in the future.
'Suddenly you have situation where Chelsea look small fry,' he said.
'Just when you thought you were climbing up and doing well, it's a whole new ball game.
'One thing is certain, it's not going to make it any easier for anyone when a club has that kind of cash.'
O'Neill continues to explore options for adding to his squad in January with a forward and a left-back his top priorities though he has as yet been unable announce any new arrivals.
'If I could have done my business by January 2, I would have,' O'Neill said.