You shouldn't take advantage of your friends.
Charlotte sometimes has outings with her friend, David, who often pays for her meals and drinks.
Charlotte wants to invite David out to dinner.
Charlotte takes David out to dinner and pays for the meal.
Charlotte and David have dinner and when the bill comes, Charlotte tells David that she has no money.
David feels like an equal in his friendship with Charlotte, and they go on to have many more dinners together.
David wonders why Charlotte would invite him out if she had no money, and gets the idea that she is using him.