App-based car services are convenient, but they're not always the most economical. Uber is looking to help you cut costs with a new ride-sharing service, dubbed UberPool, which will let you split the cost of a journey.

UberPool is launching in private beta immediately, but the company expects to expand that beta on Aug. 15. Those who get in on it will be able to call an Uber and be matched with someone nearby for a cheaper ride.

"The idea is simple. With UberPool, you share a ride—and split the cost—with another person who just happens to be requesting a ride along a similar route," Uber said in a blog post. "The beauty, though, is that you still get Uber-style on-demand convenience and reliability: just push the button like before and get a car in five minutes. When we find a match, we notify you of your co-rider's first name. Even if we don't find an UberPool match for you, we'll give you a discount on your ride."

Sharing a ride could make your trip about 40 percent less expensive than an UberX ride, the company said. "In San Francisco, how about $6 to Uber from the Castro to the Financial District? Or $10 from Sunset to SOMA?"

Uber acknowledged that "there will undoubtedly be kinks and surprises to work through," but said UberPool will be a "bold social experiment."

If you want to test it out, you can sign up at the bottom of the blog post, and Uber will notify you when it goes live in your area.

Ultimately, Uber said, the company wants to reduce the number of cars on the road. This is also something that Google co-founder Sergey Brin has said many times when discussing his interest in the development of self-driving cars. To that end, Uber is partnering with Google during this beta.

Google shares "our vision of a more energy-efficient world with less traffic congestion and pollution in our cities and are excited to be early adopters of UberPool," Uber said.