Sometimes it isn't about money, it's just about showing that you care. For example, I have this friend that has a complicated financial situation. When we go out with her, she tries to spend as little as possible, or even openly transfer the cost to people that she considers that have a better situation. But she spends more with her roommate. I don't really care about the money, but if you say that you can't go out because you need money, or expect me to foot most of the bill, and at the same time spend more with other people, I feel that my friendship is worth less.