great deal is good, large amount is also good, but we wouldn't say great amount or large deal. quantity and sum are often used to describe money, as in 'a large quantity of money', but usually to describe a single amount, like the cost of something rather than what someone earns on a regular basis. So: As a banker, he makes a great deal of money. He made a large quantity of money for his company on that deal.

Thanks Peachey have you got a link? :)

The colloquial style of the sentence suggests the proper answer is "deal". Have a look at the word-history and it'll be clear (it'll also explain why "large deal" sounds strange in this context, as Bill pointed out).