The cost of charging varies from one city to another, hence it would vary according to the city. Moreover, it would depend on the cost at which the local electricity provider is charging the price per unit.
The exact information regarding the cost of the battery of the car can be only availed at the nearest authorized service centre. We would suggest you visit the nearest authorized service center for further assistance.
Mahindra E Verito can run around 140.0 km/full charge and the claimed warranty is around 2 yr/40,000 km. Moreover, for the exact info we'd suggest you walk into the nearest authorized service centre as they will be the better person to assist you. You can click on the following link to see the details of the nearest service centre and selecting your city accordingly - Service centre