When someone tells you that something is on him, he is telling you that ❛he is paying for it❜. For example:
When entered Mama Rosa’s Restaurant, Luigi proudly turned to us and said that dinner was on him.
In some situations, a business might also offer you one of its products or services for free. Which of the following English idioms could you use ❛when a business, e.g. a restaurant or a bar, gives you something for free❜?
When a business does not charge you for something, e.g. a meal or a drink, the free product or service is said to be...
a) on the hook
b) on the hill
c) on the hop
d) on the house
Check your answer here.