Trainer badges are now available at Sprint Pokémon GO Gyms and select PokéStops. Some locations are giving away level 40 badges instead of level 30 badges, solely due to the status of being unavailable. The Trainer badge promotion is a result of the ongoing partnership between Sprint and Pokémon GO developer Niantic. To verify your nearest Sprint store that is also a Pokémon GO Gym, click here.
Source: Andrew Goldfarb