But now they’ll have the opportunity to bring in some extra cash: Uber announced Thursday that it had struck a deal with Cargo, a New York-based startup that will give drivers boxes full of items they can sell to their passengers.

The partnership will be launched in Los Angeles and San Francisco for now. Drivers can go to Uber’s support centers in the two cities, pick up boxes full of items ranging from snacks to phone chargers for free, and then sell the items to riders on a commission through an app.

If a rider wants to purchase something, they scan a QR code and pay through Cargo’s mobile website, and then the driver will give them whatever they bought. The boxes will reportedly differ in contents based on the city and time of day.

According to Business Insider, Uber estimates that drivers could make up to $100 a month from the sales; the drivers will receive $1 per order, plus a commission of 25% of the retail price. Nevertheless, Uber and Cargo won’t be giving the boxes to just any driver: they have to have a 4.7 star minimum rating on the app and be an active driver.

Uber plans to eventually expand the partnership to other cities. It also intends to integrate the Cargo purchase function into the Uber app down the road.

This article has been updated.