Knowledge: BTS concert tickets can be bought on Ticketmaster website. On the other hand, the Preview Night on the Wednesday evening before the event is open to everyone for free.

Conversation:
Do you follow San-Diego Comic Con?
I just know that it's held every year in San Diego.
Oh cool, I usually follow it every year to see the movie trailers and stuff that come out of it.
That's cool. It's apparently four days long and held in the summer.
Yeah, a lot of people put a lot of work into their costumes. It is pretty cool.
Have you ever gone to the Preview Night the Wednesday evening before it starts? You get to walk around the exhibit hall.
No, but that is really interesting. Do you know if I need to buy a ticket to see that?

Response: Hmm, you do not need to buy a ticket as it is open to everyone for free.