The state-of-the-art cloud computing service has attracted significant interests from the Internet users. However, in the existing cloud platforms, the cloud users are pure consumers; their local resources, though abundant, have been largely ignored. In this paper, we for the first time explore the resource pricing as well as the incentive issues in SpotCloud, a real-world system that enables customer-provided cloud computing service on the Internet. In this system, the resource providers are largely heterogeneous and are not forced to contribute their resources. A working business model is therefore important to offer them enough sharing incentive. Instead of setting a standardized pricing rule for unit resource, we suggest a distributed market that allows the sellers to decide the quality, quantity, and pricing of their own resources. We demonstrate the efficiency of this business model through a repeated seller competition game. The trace-analysis further indicates that the proposed business model can successfully motivate the resource sharing in our Spotcloud system.