Department H this Saturday

Do I need to buy tickets in advance?
No.

But...
¥5000/ ¥4500フライヤー持参/ ¥3000ドレスコード
飲食持込自由。会場内でアルコール類の販売はしておりません。
男女更衣室有り。

¥ 5000 Normal Ticket
¥ 4500 Bring a flyer (Discount -500 yen)
¥ 3000 Dress code (Discount -2,000 yen)

They also say to bring your own food and drink, alcohol is not sold at the event.
And, there's a men's changing room.
 
There are men's and also women's changing rooms available. Everything else is explained by @TAG Manager

I saw a lot of people gathering in front of the theater a few times before. I was always wondering what those young people were doing in dodgy end in Uguisudani.
Have fun!!