Meet the Elio, a new three-wheeled vehicle that can go 84 miles on a single gallon of gas. And, unlike its fuel-efficient hybrid competitors, it’s actually relatively cheap. A new Elio will only set you back $6,800. Of course, there are some questions of practicality: It only seats two people, and because of its unique design, the Elio has some obvious storage limitations. But, for commuters looking for a cheap, fuel-efficient way to get around town, the futuristic-looking three-wheeler could offer a solution. The three-cylinder micro-car goes on sale sometime next year …