Since you said it's gonna be your first car I'd highly suggest getting a Mehran.
Santro is a good car when maintained with care but on the other hand, keeping a Cultus is more economical. Both have 1000cc engines, so I don't think there should be a difference in fuel average. The amount of threads I see here on Cultus should be beyond acceptable. Everyone is having issues with the cooling system and AC. It's like there isn't a good car left in the market. These cars were used in ride hailing services and were taken to local technicians/mechanics, as a consequence it's hard to find a good car.
My opinion is based on personal experience. Good luck looking for a car.
