The New Relic AWS Billing integration provides visibility and control over AWS costs by monitoring application spend, creating budgets, and setting up alerts to notify when spending exceeds certain levels, allowing businesses to optimize their AWS usage and reduce costs. The integration enables users to view actual and forecasted costs for specific applications and infrastructure components, making it easier to identify areas where costs can be reduced or optimized. By combining this feature with New Relic Alerts, businesses can set up custom threshold levels to receive notifications when spending reaches certain levels, enabling them to take proactive steps to manage their AWS spend.