Uber is offering lower fares for its carpooling service if you're willing to walk a little. With Uber Express POOL, you can save around 25% compared to a normal Uber POOL trip. You'll only need to walk a few blocks to your pickup location and destination.
This services provides the lowest fares of any Uber option. Uber identifies "smart spots" that are easy for a driver to reach and not too far from passengers. This saves drivers time and energy, while not requiring much additional effort from riders.
Some rides are available for as little as $2 with this option. Right now this is only available in a few parts of San Francisco and Boston.