Cost of Living If you are single. (my personal calculations)
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Accomodation :2500QAR( One room with attached bathroom and sharing kitchen)
Food : 800-100 QAR
Transport : 300QAR

With Family
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Accomodation :3500QAR-4500qar(One room with attached bathroom and sharing kitchen)
Food : 1200-1500 QAR
Transport : Car is must - You can buy a new car for an emi of 900qar/month. Petrol is cheaper than water !!!

Hope this helps.