Some UberPool experiences:
Palo Alto to San Francisco downtown, around 2am in the morning, and it was $14.00 in total for two of us (and it was 30+ mile trip)

As expected, no other riders picked up along the way
Miami Beach to MIA (for two passengers) cost us $4.00, however picked up another rider heading to MIA as well. We went the other way and it cost us $12.00.