What is the goal of the pearl buyers?

The goal of the pearl buyers is to buy the pearl for the lowest possible price.

Now there was only one pearl buyer with many hands, and the men who sat in their offices and waited for Kino knew what price they would offer, how high they would bid, and what method each one would use. And although these men would not profit beyond their salaries, there was excitement among the pearl buyers, for there was excitement in the hunt, and if it be a man's function to break down a price, then he must take joy and satisfaction in breaking it as far down as possible. For every man in the world functions to the best of his ability, and no one does less than his best, no matter what he may think about it. Quite apart from any reward they might get, from any word of praise, from any  promotion, a pearl buyer was a pearl buyer, and the best and happiest pearl buyer was he who bought for the lowest prices.