This is all I got when I googled "her voice is full of money"

Daisy is the penultimate "material girl" being the "role mode" for many young girls too hyped up about boys and money. Whether or not Gatsby is aware of her shallowness and her improper use of wealth and status, he certainly makes a precise jab when he says that her voice is "full of money". To me, what it means is that Daisy speaks with such a carefree and careless manner, not confident, but with a sense of foolish certainty that nothing bad will ever happen to her. This can be seen by her reckless remark revealing that she loves Gatsby and the indiscreetness in her voice.This is due perhaps, to the fact that she her enormous wealth becomes the cushion bed for her errors and that she is excluded from having to subject to any moral or responsible behaviour. Her voice is also described by Nick to be song-like with an low and airy hum about it. This is most likely the technique at which she uses to lure men in a seductive fashion and thus she gains their wealth leading to Gatsby saying that its "full of money"(I dont think im quite right here).