WagonR has been one of the most practical cars.
The design is very much outdated, however, is still extremely roomy compared to newer cars and you will never feel claustrophobic.
For a 5L INR budget, and with factory fitted CNG, it costs peanuts to run and maintain the car.
Best for city runs and occasional highway runs as well.
25 km/kg on CNG is very easily achievable. Plus you have petrol too so no need to worry about long drives where CNG is unavailable.