One of the biggest questions since Tesla Motors (NASDAQ: TSLA) unveiled its Model 3 in March has been how the electric-car maker would make customers pay for access to its robust Supercharger network. After all, the convenient long-distance travel enabled by these chargers, which can provide up to 170 miles of charge in 30 minutes, are one of the company's best perks for its vehicle fleet, compared with the charging options available for electric cars by other manufacturers.But investors and customers may be getting a peek at Tesla's future monetization model for its Supercharger network.