Peer-to-Peer (P2P) energy trading describes flexible energy trades between peers, where the excess energy from many small-scale Distributed Energy Resources (DERs) is traded among local customers. The feasibility of applying P2P energy trading to reduce costs for energy consumers, and to increase income for DER producers in a community microgrid was investigated. Three representative market paradigms were proposed, i.e. bill sharing, mid-market rate and an auction based pricing strategy. Each of them specified detailed business models, local energy exchange prices, as well as quantified individual customer's energy costs. An example of each methodology applied to a residential community microgrid with PV systems, validated the effectiveness of the proposed P2P trading mechanisms and identified the benefits.