Pasar malam business also have a lot of things to consider. Location, What you gonna sell, your competitor, season, etc. Some items the profit margin is really low because too many seller of the same things so they keep fighting to survive. Unless you are talking about selling illegal things, if you know what I mean  . i have seen graduates who throw away their job to do this full time. Now also got franchise concept business for pasar malam. the type like the uncle bob chicken and bubble milk tea sort of thing. you gotta let us know what you planning to sell first, maybe from there we can give you more feedback.