A new round of discount leases on mainstream-brand plug-in cars such as the Nissan 7201.TO -1.38%Leaf or Fiat F.MI +0.93%500e, combined with federal, state and local electric-vehicle incentives, could make a battery-electric car an extraordinarily economical way to get around for drivers. There are two big caveats: Drivers need to live in states offering tax incentives and can't drive very far in a single day.

 

Electric cars are still a long way from achieving mass appeal. Plug-in cars accounted for less than 1% of total vehicle sales in the U.S. during the first four months of this year, according to data compiled by the website hybridcars.com. But the flurry of discounts and public subsidies has more consumers refiguring the math. Plug-in sales more than doubled in the first four months of 2013 compared with a year earlier.