It's not an easy answser $x is sufficient. What are your needs (and wants) - what type of housing, where, furnished or unfurnished, which school, does your employer cover any of these costs? What's your lifestyle, do you need access to a beach/pool/gym - what kind of facilities?

Do you dine out often? KFC or 5*hotels?

Lots of people here live on less than 10,000 Riyal a month and pay rent out of that and maybe education