Emerging computer vision applications of smart camera networks (SCNs) often require that the network cameras operate under limited or unreliable power sources. Therefore in order to extend the SCN lifetime it is important to manage the energy consumption of the cameras which is related to the workload of the vision tasks they perform. Hence, by assigning vision tasks to cameras in an energy-aware manner it is possible to extend the network lifetime. In this letter, we address this problem by proposing a market-based solution where cameras bid for tasks using an adaptive utility function. The early results for different SCN configurations and scenarios indicate that the proposed methodology can increase network lifetime.