This paper aims to give an insight on the motivation of end-users within an energy community to encourage other users to join by sponsoring them. The proposed community organization is divided in two stages: first one for energy management and second one for costs allocation in an energy community (i.e. the way the overall bill is distributed among the members). In particular, two billing allocation approaches are proposed and account for end-user's preferences and their willingness to pay. Those strategies are based on an approach designed to set individual tariffs while preserving the properties of traditional allocation methods. This work gives perspective on different end-user's preferences and facilitates the understanding of energy communities farther than merely financial enterprises.