It could be tough getting enough Poké Balls when you have to stay at home and can't visit PokéStops. To make sure you have enough balls to catch monsters with, Niantic has started selling a 100-Poké Ball bundle for 1 PokéCoin in the Pokémon Go shop. The company has launched a rotating 1 PokéCoin bundle that will change every week and will be available as one-time purchases. It's also increasing daily bonuses and giving you three times the Stardust and XP for your first catch of the day, as well as adjusting the number of gifts you can open in a day to 30.
Source: Niantic (1), (2)