You can get one at the venue. They'll still them.
How much is one? do I really need to buy one? I mean I'm just going for one concert and that's all. I probably won't go to any other concert.
the ticket itself is expensive. i don't think it's really a requirement for you to buy a lightstick if you can't afford it. that doesn't make you less of a fan if you don't have any merch.
You don't need to buy one if you don't want to or have no money for it. If you plan on going to another concert of theirs in the future then I'd say it's nice to have it, but it's not required.
I'm going to go to BTS concert next month,I'm wondering if I need the lightstick?