He's given similar comments before, and I think this translation is not accurate in terms of what he actually means. I'm pretty sure he means that signing a player for 30 million isn't necessarily useful. I don't think he categorically denies doing it. But he means to say that signing a player for 30 million won't guarantee you success. And with the flops that were Amauri, Felipe Melo and Diego, and by looking at clubs like Real Madrid over the years, the man has a point.
The important thing is to find the right pieces for the team and integrate them properly. Sometimes they cost little, sometimes they cost nothing and sometimes they can cost for example 30 million. What's important is to get the right men for the team and the coach's system, regardless of their price.