If you’ve been toying with the idea of buying a hybrid car, the cost equation is tilting in your favor. Until recently, buying a hybrid meant you were willing to shell out for a pricier car because you believed in helping the environment or because you liked to own the latest high-tech gadget. Auto-research firms found it could take up to 15 years, depending on the model, of gasoline-pump savings to offset hybrids’ higher sticker price. …

If you’re lucky, as I have been in several cities, you might occasionally flag down a rare taxicab bedecked by its driver with disco balls, mood lighting, tinfoil hearts, or even a menagerie of stuffed animals. This week, San Franciscans got the option to hitch a ride in a novelty taxi of a different sort, as start-up Green Cab’s single hybrid Honda Civic hit the road. Next month the fleet could total five gas-electric taxis painted in low-toxic green paint. …