We present models for bartering of resources on grids. Bartering models can be useful for making resource allocation decisions in grids and perhaps even for building a so called barter grid whereby distributed resources such as electronic media can be bartered. Grids allow various resources to be shared among many users. This sharing however definitely does not mean that everyone will have unrestricted use of the resources. Some mechanism such as pricing or quotas can be employed in order to enforce controlled sharing of resources. A barter model for resource sharing can enable people or computer centers to directly get something in return for letting their resources to be used by others. We utilize directed hypergraphs to develop a barter ...