Hello Tacomaman,
This had to have arisen out of his being a millionaire's kid. His entire life, he has never had any real friends. He has always wondered if people only had anything to do with him because he was loaded and they were really attracted not to him but his money. Eventually, he must have simply assumed the only reason anybody had anything to do with him was because of his money. I bet he doesn't know what real friendship even is.
It's very sad, actually. He has no peers, nobody he can identify with. And the lessons he has learned is that everyone has their price. Well, either they have their price, or they simply cannot be bought. The ones who cannot be bought, he insults because of it.