You need a new car, and you want to do your bit for the planet. So you're weighing your eco-friendly options:

There’s the Prius, of course. Cost: $25,000. Mileage: 46 mpg.

The new Smart cars are cheaper--$17,000 for the two-seater. Mileage: About the same.

Or, maybe you have $100,000 to burn (unlikely, given the recent financial meltdown) and you're eyeing the 135 mpg Tesla Roadster, the sexy sports car being developed by PayPal co-founder and private-sector spacecraft developer Elon Musk.

But wait. Not so fast. There's yet another option: The Aptera. At $30,000 it’s a wee bit pricier than the Prius or Smart car. But you'll more than make back the difference in gas savings. Its mileage? 300 mpg.

Slated to go into production later this year (or maybe next year, the way these things go), the three-wheeled two-seater actually looks more like a spaceship than a car—the result of an aerodynamic design which is key to its fuel efficiency.

The other part of the high mileage equation are the light-weight materials like fiberglass used to build the car’s shell, meaning the engine has less overall weight to move, in turn requiring less energy. And yes, the Aptera folks say they’ve made sure it exceeds safety standards.

There are other green features too. Roof-top solar panels power an always-on climate control system that keeps the car perpetually cool, requiring smaller air conditioners. Rear-mounted cameras replace rear-view mirrors, further reducing wind drag.

The car will eventually be available as either an electric-only plug-in or a Prius-like hybrid. The electric version will need to be charged every 120 miles, which could cramp your style if you have long commute. The hybrid will have a range of 600 miles, but you’ll need to partially rely on gas for that.

California-based Aptera is currently taking orders for the vehicles, but only from Golden State customers, to ensure it can provide post-sale maintainance services.

Realistically, I’d probably feel self-conscious driving around in something that looks like it belongs on the set of the Jetsons. But if it helps the planet, hey I’ll take one for the team.

More goodies:

· Luscious photos at AutoBlogGreen.com

· Aptera’s photostream at Flickr

· Aptera’s YouTube channel