Embodiments are directed to managing a prepaid server-arbitrated group communication session within a wireless communications system. A server receives, from a session originator, a request to setup a prepaid group communication session with at least one session target, the prepaid group communication session requiring each session participant to have an available prepaid account balance above a threshold level. The server sends a query to an online charging system to determine whether at least the session originator has a prepaid account with an available balance at least equal to the threshold level. The server initiates setup of the requested prepaid group communication session without waiting to receive a response to the query, thereby reducing latency associated with set-up of the prepaid group communication session.