NEW YORK ( TheStreet) -- One of the most common questions about plug-in electric cars is the reason for buying one. In this article I will break down the key argument and its alternative:1. Cost: Is there a positive payback? 2. Premium: If there is no payback, is there another reason to "pay up" the extra money to buy a plug-in electric car? Let's start with cost and payback: With an electric car, you can drive mostly somewhere between three and four miles per kilowatt hour, depending on the model. The average price of electricity in the U.S. is between 11 cents and 12 cents per kWh. Let's for a moment disregard the fact that more and more people now can charge at night when rates are considerably lower than 11 cents per kWh.