Well, it depends on just how little money you have, and just how much your concerts cost. It also depends a lot on the degree of fallback options you have - For instance, does running out of money mean you move back in with your parents for a bit? Or does it mean you're about to apply for public housing? It also depends on whether you are only looking out for yourself, or if anyone is depending on you.

A $20 show? I'm down. But I have friends who claim "not to have much money" yet they spend $300+ on concerts (with the + on hotels, etc).

And I just don't get it. I am pretty sure I love concerts as much as the next guy but an extra $300 can buy me almost half a month being able to pay rent and basic living expenses. That's a lot of piece of mind. Personally I would not feel safe spending that kind of money money until I had at least a year's worth of savings. When I imagine running out of money I imagine total chaos for myself, my younger siblings, my older parents, everyone. I'm not even poor, I can't imagine how hard it is for people who are actually poor.

On paper we might make the same amount of money, but it's not the same thing.