Systems and methods for providing user-centric device-based data communications cost monitoring and controls. In an embodiment, the method operates by sending a registration request associated with a subscriber session, determining current data usage associated with the subscriber, and sending data usage thresholds. The method further comprises sending quotas associated with the subscriber session after collecting data usage information associated with the subscriber session. The method receives a notification at the subscriber's mobile device when a pre-determined quota is exceeded during the subscriber session to control data usage. The system communicates with a usage policy server and a usage policy application. The usage policy application allows a subscriber to alter terms and service tiers of a subscription. The usage policy application displays current data usage information on a per-network and per-application basis using subscriber profile information, subscriber session information, and prior subscriber usage history received from the usage policy server.