What should I do with the money?

I have 150 euro and do not know if I should save the laptop or PC or if I should rather get concert tickets…

Save up!

Nobody can tell you that. For me, a concert visit is not worth much if that is something else with you ok. Nobody will be able to tell you that

How important is the laptop? And which artist do you want to watch?

I would save it if I assume that the concert visit is not so important to you as you weigh it up with a laptop. Concerts are a lot of money for a short time, so I personally think that it must be one where you absolutely want to go. And you have something longer from a laptop. But that's just my personal opinion and in the end you have to decide that.