Tesla currently provides unlimited free access to its Superchargers for owners of its high-end luxury electric cars, the Roadster, the Model S, and the Model X. The company’s Superchargers, which can charge a car in 30 minutes or more, are strategically placed around the country to enable customers to drive long distances.

More often, Tesla (TSLA) customers charge their car batteries at home or the office using slower charging systems. Tesla built its Supercharger network to encourage potential electric car owners that its cars were as convenient as gas-powered cars.

But the Supercharger infrastructure, and the electricity used to charge Teslas, costs the company money. It’s a cost that the luxury car maker has accepted until now, but apparently may stop doing so for the $35,000 Model 3.

If the company does end its practice of providing free unlimited use of its Superchargers for owners of its first mainstream car, it would represent one of many potential concessions that Tesla may make to deliver an electric car for $35,000 with a competitive driving range. Creating a car that costs less than half of its other models will be a major challenge.

For more on enthusiasm over Tesla’s Model 3 watch our video.

In response to a question from a Tesla customer during Tuesday’s shareholder meeting, Musk said that providing free and unlimited long distance charging at Superchargers is a cost that Tesla wants to “decouple” from the Model 3.

“It will still be very cheap, and far cheaper than gasoline to drive long distance with the Model 3, but it will not be free long distance for life unless you purchase that package. . . it has to be something like that,” said Musk. Tesla declined to elaborate on Musk’s comments.

Musk said he wished that Tesla could achieve the low cost economics of the Model 3 without charging for the Supercharger costs. “Tesla’s motivation is to make electric transport as affordable as possible. That’s what informs all of our actions,” said Musk.

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If Tesla starts charging for additional features “it’s not because we want to make things more expensive, it’s because we can’t figure out how to make it less expensive. That’s all,” said Musk.

Tesla unveiled the Model 3 design at an event in Los Angeles last month and also simultaneously opened reservations for the car. Within a week of the event, close to 400,000 people had put down a $1,000 deposit to reserve the Model 3, despite the fact that the car won’t be available until late 2017. Musk has called the Model 3 unveiling the biggest product launch in history.

But now Tesla has to figure out how to produce and sell the Model 3 in those high volumes.