In Mobile Ad hoc networks, communication between distant nodes relies on cooperation of intermediate nodes to forward packets to the destination. But, a selfish node for saving its resources (e.g. battery power and bandwidth) does not cooperate and drops packets which are not belonging to it. If there is no mechanism to cope with selfish nodes, cooperative nodes will be overloaded, hence network performance will degrade. In this paper we propose a distributed scheme to counter with selfish nodes and to enforce cooperation in pure mobile ad hoc networks. The proposed scheme is a combination of reputation based and currency based schemes which mitigates defects and improves advantages of them. The proposed scheme neither needs central control nor a priori trust between nodes. The proposed scheme detects selfish nodes faster and more accurately. This scheme fairly increases throughput of well-behaving nodes and decreases selfish nodes? throughput.