Why would she come up with a excuse for not meeting when she asked me?

There's this friend of mine, but we never really met in person. One day she asked me if I wanted to go to a concert with her if she had enough money. Of course I said yes. Two weeks before the concert I asked her if the concert was still on. She wasn't certain, because she was short on money. A week before the concert I see on facebook that she's going to another concert a couple of days before our meet-up (and more expensive). So I ask her: "I guess we're not going anymore?" I was right... Now I found out she's also going to another country to see a band and she's attending yet another concert in her neighbourhood (all in a span of three weeks). Clearly money wasn't the issue... Why would she ask me in the first place? I want to confront her, but I don't want it to turn into an argument :/