Living expenses are pretty cheap here.
You'll probably not spend more than 2000 Qar a month on food.
Water and Elec depend on what property you are given or you rent. Company gives you 300 Qar a month which just about enough.
90% of people own cars. The Taxis are cheap but often hard to get hold of everytime you need them. Small 4x4, brand new costs about 90000 to 120000 Qar. 100% Loans are easy to get.
Total expenditure depends on what you like to do in your spare time, but if you are careful you shouldn't have to spend more than 6000 Qar a month on everything!! (except rent)
Hope this helps.
SSS