Prohibitively expensive might not specifically reference to the monetary cost of the class. You could probably scrounge up $100 a month for Kumon even from much

Prohibitively expensive might not specifically reference to the monetary cost of the class. You could probably scrounge up $100 a month for Kumon even from much lower income families, but many children in lower income families end up having a real opportunity cost in going to a summer class. The parents may not be able to drive the children to the class, the children might be pressured to get a summer job to help pay for the family, etc.