Heterogeneous multi-cores that integrate cores with different power performance characteristics are promising alternatives to homogeneous systems in energy- and thermally constrained environments. However, the heterogeneity imposes significant challenges to power-aware scheduling. We present a price theory-based dynamic power management framework for heterogeneous multi-cores that co-ordinates various energy savings opportunities, such as dynamic voltage/frequency scaling, load balancing, and task migration in tandem, to achieve the best power-performance characteristics. Unlike existing centralized power management frameworks, ours is distributed and hence scalable with minimal runtime overhead. We design and implement the framework within Linux operating system on ARM big.LITTLE heterogeneous multi-core platform. Experimentalevaluation confirms the advantages of our approach compared to the state-of-the-art techniques for power management in heterogeneous multi-cores.