Those who run the workhouse view anyone who will take one of the children off their hands as "good" for the child. One less child in the home is one less mouth to feed.
They had gotten rid of Oliver once, to an "infant farm", but he is returned to the workhouse. There, he causes more trouble for the crime of asking for more food.
The workhouse decides to offer him as an apprentice to anyone who will take him. Gamfield comes up with the five pounds; and that's enough for the workhouse.