Sonic Drive-In does offer an app that allows customers to place orders, customize their meals, and access exclusive deals and promotions. The app is designed to enhance the overall dining experience, making it easier for users to enjoy their favorite Sonic menu items. Generally, the app itself does not feature in-app purchases for additional items beyond what is offered on the menu. Instead, customers use the app to browse and order food from the Sonic menu, which includes various burgers, beverages, and sides. Any costs incurred would be related to the selection of food and beverages customers choose to order through the app. For the most accurate and current information regarding the app and any possible changes, the official Sonic website or the app's user interface may provide valuable insights.