Agree with NoSig... If you don't have accommodation included then you will have 2 choices, either live in a compound or live outside in regular saudi society. To live outside is as cheap as you'll find anywhere in middle east with a shared apartment in the bachelor part of town going for about 700Sar/month but the compounds are just insanely expensive, anything from 650U$D/month to well over 1000U$D. If you are paying that then u will have not much left at the end of the month. You also have to consider the cost of transport unless you have your own car and fuel is the cheapest in the world here.