The increasing demand of mobile applications creates challenges for mobile devices on energy consumption and data usage. As a solution, device-to-device communication can serve as a powerful paradigm in future cellular networks to enable local cooperation of mobile devices. By leveraging social awareness, users can share surplus communication and computation resources on their mobile devices to stimulate beneficial cooperation, which can cut down on energy consumption and data usage. In this article, we propose a joint task-data offloading framework for mobile devices that have insufficient energy budgets or data usage budgets. Based on the proposed framework, a mobile device association problem is formulated and solved by exploiting matching-based and game-theory-based schemes. Extensive numerical results show the effectiveness of the schemes for the proposed framework in the reduction of energy consumption and data usage.