I've known of people who always wanted more money (and everything else), but were willing to spend money freely - if only to impress or buy their friends.
Such people are greedy, but not stingy.
I have also known of people who did not have much money and were not obsessed with getting it, but were unwilling to spend it.
They were stingy, but not greedy.
To be sure, there are plenty of people that are greedy and stingy at the same time.
I would be more inclined to call the kid in the example stingy. If he was also demanding more toys and candy, he could also be called greedy.