http://www.ccel.org/ccel/mcgarvey/gospels.vii.xliv.html
16 But Jesus said unto them, They have no need to go away; d 5 Jesus therefore lifting up his eyes, and seeing that a great multitude cometh to him, saith unto Philip, Whence are we to buy bread, that these may eat? 6 And this he said to prove him: for he himself knew what he would do. 7 Philip answered him, Two hundred shillings’ worth of bread is not sufficient for them, that every one may take a little.
Notice how Phillip doesn’t answer the question that Jesus asks.
Jesus asks this: Where can we buy enough food to feed all these people?
Phillip answers: We don’t have enough money to buy food for all these people.
But that wasn’t the question.
Jesus is making the point that it would take a miracle just to feed all the people. Phillip doesn’t think that far; he is examining his own resources (and that of the disciples) and coming up short. He doesn’t think beyond that. In Phillip’s world, it may be possible for the disciples to have enough money to buy food for everyone, as crazy as that sounds. But Jesus is a step ahead. Even if they had unlimited money, there still wouldn’t be enough food in the villages around them to feed the crowd. The only way for them to be fed is through a miracle.