Ferguson was interested in taking the Belgium international to Old Trafford - but not at the reported £34million Chelsea paid to French club Lille.
"There is a borderline in terms of what you would think is a good signing for United," he said.
"I see some values on players, like Hazard for instance. To me it was a lot of money. He's a good player, but £34m?
"What we're finding anyway, the climate for buying these top players - not just the transfer fees, the salaries, agents' fees - is just getting ridiculous now.
"In the Hazard deal, Chelsea paid the agent £6m. The (Samir) Nasri situation was the same.
"It's all about what you think is value for a player. I am not envious of those deals at all. We placed a value on Hazard which was well below what they were talking about.
"So if it doesn't work, well we're not worried about that. We think we've got good value in (Shinji) Kagawa."