Dacia Spring 27kWh Extreme 65 48kW 5dr Auto Electric Hatchback, , This is a cheap electric car to buy. If you have off-street parking and home charging running it will be even cheaper, with negligible costs given the small battery can do a full charge overnight on your off-peak tariff. Benefit In Kind taxation if you use it as a company car stays at 2 per cent for another year, then rises slowly, making it still the cheapest tax you can pay for years to come. The Extreme 65 version comes with emergency braking, hill start, lane keeping assistance (as annoying as ever) and driver attention warning.