A method and system for implementing a prepaid service in a packet-switched mobile communication network, in which information requested by a mobile station is delivered to the mobile station so long as the subscriber has maintained a sufficient prepaid balance from which the service charges can be deducted. An access point name definition, which points to a service node via which access to or use of an associated prepaid service is provided, is defined. A control server is used to monitor the service traffic between the mobile station and the content server after the access point name definition identified in an activation request for data service has been sent from the mobile station. Traffic monitoring continues as long as the data service is active, and the prepaid service balance in a billing database is dynamically updated to reflect the subscriber's ongoing use of the data service based on the continued monitoring of the control server.