Many myths about mpg, automatic vs. manual, size of power plant, etc.
Government test figures at
Fuel Economy

Here in western Canada, weekend drives of 100-300 miles or more are not uncommon, to visit parents, kids, the farm, the vacation property, the ski resort, etc., often hauling several people, their gear and supplies. Very small cars are usually a second car, used in town only.
Note- almost no difference between automatic and manual, automatic now often offers slightly better mileage. A couple of pick-ups and SUVs are listed; very popular and useful here. U. S. data are in miles per gallon, you will have to do the conversion to liters.

A sampling:
Toyota Prius -    city 48 mpg, hwy 45mpg
Toyota Corolla - city 26, hwy 35
Toyota Camry 2.4l - city 21, hwy 31
Toyota Tundra 4.7l -   city 13, hwy 16 -4WD pick-up
Toyota 4-runner, 3.5l - city 19, hwy 28 -4WD SUV

Chevrolet Arco 1.6l - city 24, hwy 34; manual, auto 23-32
Chev Malibu 4cl auto - city 22, hwy 32
Chev Silverado 5.3l - City 14, hwy 19 -4WD pick-up

Ford Fusion 2.3l - City 20, hwy 29 (auto or manual)
Ford Focus 2l - City 24, hwy 35 (manual), city 24, hwy 33 (auto)
Ford Taurus 3.5l - City 17, hwy 24 -AWD

Audi A3 2l - city 22, hwy 29

BMW 328 3l - city 19, hwy 28
MINI Cooper 1.6l - city 26, hwy 34

Honda Civic Hybrid 1.3l - City 40, hwy 45

Jeep Grand Cherokee 3.7l, 6cl - City 15, hwy 19 -4WD SUV

Smart car   -       City 33, hwy 41

Porsche Carrera 3.6l - City 18, hwy 26   

The so-called Smart car seems to be a bad choice; both Honda and Toyota have models that do better, and are safer- the Smart car should not be allowed on the highway. There ae a couple of sports car enthusiasts in the neighborhood who have Carreras as second cars.