2013 Chevrolet Volt - front three-quarter view

There was a time not too long ago when General Motors would've been happy with 1,500 Chevrolet Volt sales per month. Apparently, that time has passed.

GM is apparently looking to goose sales of its extended-range plug-in by offering rebates of as much as $4,000 per vehicle, Inside EVs says, after finding the discount on Chevy's Build Your 2013 Volt site. And if you're currently leasing a non-GM vehicle, you can get an additional $1,000 off.

Chevrolet appears to be responding to increased competition for the $39,995 Volt from other plug-in vehicles. Nissan cut the price of its Leaf battery-electric earlier this year, while Ford debuted its Fusion and C-Max Energi plug-in variants. A number of low-cost EVs are also available, mostly in California. Inside EVs notes that Chevy has about 9,000 examples of its 2013 Volts in inventory to clear out before the 2014 model arrives.

Through May, Volt sales are little changed from a year earlier at 7,157 units. We'll see how the numbers change once the next-gen Volt becomes available. We've already heard it'll be "thousands" cheaper, but we won't complain about the chance to get a better deal on one today.