Success of peer-to-peer applications in many cases is attributed to user altruism, where a user contributes some of its own resources to facilitate performance of other users. This observation has been corroborated with some experimental evidence. In this paper we make a first attempt to demonstrate that there are many scenarios where peer-to-peer resource sharing is a natural behavior that selfish users can use to improve their own performance. In particular we examine such natural incentives that exist in a streaming media application which lead such greedy users to cooperate and share resources with each other in forming an efficient overlay multicast tree. We define a freestyle Bazaar environment in which streaming media receivers interact with each other and cooperatively construct an overlay tree for improving their perception of media streams from a single server. Through simulations we demonstrate the efficacy of our proposed environment. Categories and Subject Descriptor...