Given the perception that employing usability evaluation method is expensive and timeconsuming, industries are sceptical to integrate usability throughout the product development lifecycle. A Cost-Benefit Analysis is claimed to be the most feasible approach to calculate the cost incurred in any employed usability technique, and the estimated return on investment (ROI) and benefits gained in the long run. This paper highlights two usability evaluation methods, namely Usability Testing and Heuristic Evaluation, which were employed to determine the most cost-effective approach based on a study for an online shopping website. The Usability Testing approach was conducted in context of the Common Industry Format for Reporting Usability Evaluation whilst the Heuristic Evaluation was conducted referring to Nielsen’s (1994) Discount Usability Engineering approach. As a result, the analysis parameter of Cost-Benefit Analysis for both usability evaluation studies were based on the elements employed in each method. For instance, the costs for Usability Testing and Heuristic Evaluation were justified on pre-evaluation, post-evaluation of the evaluator on the time spent for the evaluation, and miscellaneous charges involved. On the other hand, the estimated benefits were referred to the estimated increased sales revenue, an average profit margin of a product sold and an increased conversion rate after optimizing usability. A summary was drawn on the most cost-effective method for usability evaluation studies on an online shopping website. In view of the study conducted, this paper also reports on the effectiveness of applying Cost-Benefit Analysis for both usability evaluations.