DON'T BUY 660cc crap.
BUY A 2005-07 Honda city it gives a good mileage and is way better than a small 660cc box.
I have an alto. it gives 16.5 in city in summers and 17-18 in winters. I regret having a 660cc box.
City should give you two or three kms per liter less but it will be a much better car.
Take your time and find a good honda city "chooa" shape.
If you are determined to make the same mistake i made then go for a car with auction sheet. 99% of jap imported cars are damaged.
Search the blog for Japanese imported cars and you will find that they most imported cars are damaged.
The thing is that we as Pakistanis buy damaged Japanese cars and don't buy damaged desi made n run cars.
japani gari main koi heeray nahi jaray hotay.
Agar style chahiyay then i can hook u up with a 660cc Honda N-One. It is has a beautiful design with lots of features that other 660cc cars don't have. It has new tech of "earth dreams" engine in it which means it will be fuel efficient.
Before you buy try finding the engine model for the car you are selecting then go online and search for mileage for the car. as per my research on my alto 660cc i have K6A engine which is giving good mileage as per online ratings.