The National Electricity Market of Singapore (NEMS) is designed to promote the efficient supply of competitively priced electricity. In Singapore, the Power Demand and Uniform Singapore Energy Price (USEP) vary in half hour periods. This paper presents a Multi-agent System (MAS) to effectively manage the energy sources of a microgrid depending on the power requirement and market price. The MAS is developed in Java Agent Development Environment (JADE) which interfaces with Matlab-Simulink to validate the control and management of microgrid in a simulated environment. The MAS determines the microgrid's mode of operation based on the fluctuations in the market price and power balance between generation and demand. In this paper, three scenarios have been formulated with the help of real-time data from Energy Market Authority (EMA) to demonstrate the actions taken by the proposed MAS.