Solar energy sharing among prosumers via peer-to-peer energy trading in a net metered community microgrid is studied. The trading interactions among the prosumers are analyzed as a market with transferable payoff. The outcome of the prosumer's trading interactions is predicted by the competitive equilibrium of the market, for which a closed form expression is derived. The competitive equilibrium also offers a stable/in the core cost allocation mechanism for the energy-sharing prosumers in an aggregated microgrid. The competitive equilibrium reveals that, in a net metered microgrid with a lower to medium level of solar penetration, all the economic benefit goes to the prosumers who have solar panels. In other words, even though a key social incentive for solar energy sharing is to let consumers without solar panels to have access to locally generated solar power from their neighbors who have solar panels, their economic benefits from doing so are however fundamentally limited.