Not counting plug-in cars, the 2012 Toyota Prius c is the most gasoline-stingy auto on the U.S. market, with a combined city/highway rating of 50 miles a gallon, according to the federal government.

Better yet, the starting retail price of $19,710 means the Prius c has the second-lowest base price of any gasoline-electric hybrid in the country.

No wonder the 2012 Prius c small hatchback with four-cylinder engine mated to two electric motors and battery pack is a compelling offering for budget-minded consumers and environmentalists who want to reduce oil usage and air emissions.

The gas-electric hybrid with the lowest starting retail price in the United States is the 2012 Honda Insight hybrid, which starts at $19,290. But the Insight's combined city/highway rating from the federal government is 42 mpg.

The new-for-2012 Prius c showcases its thrift, even including an onboard computer that can tally how many dollars a trip is costing while the car travels.

For example: A 62.2-mile trip at mostly highway speeds in a test car that didn't get quite the federal mpg cost just under $5.50 at the going price of $3.67 a gallon for regular fuel. All the driver had to do was input the price of the gasoline in the tank and the dollars rolled up in the instrument panel as the miles passed.

Computers in most cars display miles-per-gallon but don't offer a way to input the gasoline price to give the driver the continuous fuel cost of travel. A driver typically must multiply the price-per-gallon by the mpg on his own.

But be aware: The Prius c is a small, five-door hatchback.

It's 13 feet from bumper to bumper -- which is 19 inches shorter than a "regular," five-seat Prius hatchback and 4.3 inches shorter than the small Honda Fit.

The five-seat Prius c also weighs a lightweight 2,500 pounds and can be buffeted by high winds.

The Prius c isn't sporty, either. Combined horsepower from the engine and two electric motors is 99, which is 35 less than what's in a larger, regular Prius.

But Consumer Reports expects above average reliability.

The manufacturer's suggested retail price, including destination charge, of $19,710 is for a base, 2012 Prius c One hatchback with continuously variable transmission that maximizes fuel economy.

Price can rise to more than $25,000 with the top trim level, Prius c Four, and an option package or two added.

Prius c Four includes heated outside mirrors with turn signal indicators in them, alloy wheels, heated front seats with SofTex material, navigation system, and tilt and telescoping steering wheel with controls, among other things. A moonroof is an option even on the Four.

Besides the Insight, lower price, higher mileage, non-plug-in hatchbacks include the 2012 Scion iQ three-door hatchback with combined city/highway mileage rating of 37 mpg and starting retail price of $15,995. The 2013 Hyundai Accent five door with combined city/highway mileage rating of 34 mpg and 138-horsepower four cylinder starts at $15,570 with manual transmission. The iQ and Accent are not hybrids.

A traditional or regular 2012 Prius hybrid with bigger engine and larger passenger compartment than the Prius c has a starting retail price of $24,760.

The larger Prius has the same 50-mpg federal government rating of the Prius c in combined city/highway travel, in part because the Prius c isn't quite as aerodynamic and has an older, slightly less efficient engine. But the Prius c outdoes its older, larger sibling in city mileage, where the federal rating is 53 mpg instead of the bigger Prius' 51 mpg.

The test car, a top-level Prius c Four, was always above 41 mpg even when the driver drove hard. It easily averaged 44.5 mpg in combined city/highway driving without the driver trying to maximize fuel.

Most notable was how smoothly the Prius c moved from electric power to gasoline power. There was no telltale sensation of stumbling or hesitation.

The 1.5-liter, double overhead cam four cylinder operates on the fuel-saving Atkinson cycle, and acceleration takes a while -- 0 to 60 miles per hour takes 11 seconds.

The gas pedal in the tester even seemed a bit stubborn to go down, providing resistance especially in "eco" mode, as if to ask if the power really was needed.

The Prius c has an older-technology nickel metal hydride battery pack, rather than lithium ion.

Body control is acceptable for such a small car. But the car's interior can be noisy, with sounds from nearby cars readily coming into the passenger compartment and wind noise getting loud above 55 mph.

The turning circle is barely over 31 feet if the car wears standard 15-inch tires, but the tester had optional 16-inchers, which made the turning circle a larger 37.4 feet.

The Prius c steering wheel is small, and the steering felt numb at times in the test car. The car horn sounded wimpy. Certainly, this is not a sports car.

Passengers felt road vibrations much of the time, and bounced up and down a good bit when the small-wheelbase Prius c traveled over a lengthy highway bridge with expansion cracks.

Three adults in the back seat are a tight fit across the narrow Prius c, and they sit on short cushions.

Front seats needed more lumbar support in the tester.

Meantime, the uplevel SofTex material in the test car was black and got hot in summer sun. Thank goodness the air conditioning came on fast.

The Prius c dashboard also was black, with the less-textured, less expensive-looking plastic pieces up near the windshield and better-looking plastic closer to passengers.