Hey. I'm here. Here's how it works. There is no rent since the point of these complexes is to safeguard the monsters inside... If a monster couldn't pay rent and had to be kicked out... that would be bad for all monsters. This also means that food is also free.

That being said, anything extra is payed. You can ask cleaning services to help clean your room. Gym and pool are payed. Doctors are free but you need to pay for the supplies.