Why do you want to throw a party for 100 people?
You're not the boss and you know you couldn't afford it.
Just throw a party for people in your department or some close friends.
That way you will get quality , not just quantity snack+time.
Don't get me wrong but I found it's rediculous as a staff to throw a birthday
party for 100 people in office with 500 Baht.
You will make talk of the town!