No pet is "free". A cat, even if you do not pay for it will cost you at least QAR1200 - 1800 in the first year (perhaps more) for vaccinations, vet checks, microchipping, and spaying or neutering (and if you don't plan to spay or neuter don't get a pet at all).

Then the vaccinations and vet checks which should be done annually will cost you at least 400 - 600 Riyals if the cat is healthy and requires no other expert care.

you will have to brush a longhaired cat daily.

Food, cat litter etc. probably about QAR100 per month (1200 per year).

You say you have no money - where are you going to get the money to pay for all of the above that responsible pet owners pay for to care for their pets properly?

I'm sure you love animals/cats - but the reality is they are not cheap or always convenient to look after. What is your plan if you have to leave Qatar? Transporting a cat will cost at least QAR1500 (including all the paperwork etc)