Pricing is pretty competitive. For a traditional cab from the Metreon to Sausalito's Cavallo Point, it's about $40. That doesn't count the massive traffic on the bridge approach, or on the bridge itself. The new Water Taxi , allows you to walk a few blocks to Pier 1 1/2, and zip away in traffic-free comfort for only $25 more. Not too bad, to ensure you make that table at Murray Circle. They do offer discounts for frequent riders, and, like any cab, the fare is not per person.
Truthfully, I'd love to see an SFO run: now THAT is the way to fly.