This paper presents the design, development, and evaluation of an Automated Expense and Parcel Notification System (AEPNS) for residential property management. The system integrates a web-based application, a PHP-based backend, a MySQL database, and third-party notification services (LINE Notify and SendGrid) to automate billing and delivery alerts. The evaluation combined functional, integration, and user acceptance testing with affective assessment using the International Positive and Negative Affect Schedule Short Form (I-PANAS-SF). Results from real-world deployment demonstrated reductions in administrative workload and communication latency, alongside high levels of user satisfaction and positive engagement. In addition to reporting operational gains, this work contributes (1) a lightweight and deployable architecture tailored for small to medium-sized residential communities, (2) dual evaluation metrics that combine operational key performance indicators with affective user responses, and (3) practical insights into system scalability, maintainability, and compliance with security and privacy requirements. Identified limitations, such as procedural code constraints and third-party service quotas, inform a clear roadmap for future development that includes migration to a modular framework (Laravel), multilingual notification support, and a resident-facing mobile application. These findings indicate that even low-cost, API-driven solutions can act as scalable enablers of digital transformation in emerging digital economies.