you can manage with QR4000 to 5000 a month. But before taking decision, you have to consider the following.
* with this salary, you cannot get family visa.
* you cannot change job in Qatar.
* the job at Qatar has it's own risk.
* how is the reputation of the employer, do they keep their commitments.
* How many days leave and Air ticket.
* if you are well settled in your country, think well before.
* your career growth.
* does it include the transporation or will company provide, tranporation will be expensive if you travel by taxi, public transport is not available for all places.

Wish you all the best.