Online retail has transformed the landscape of financial management, requiring new approaches to revenue accounting, cost analysis, and profitability metrics. This chapter provides a comprehensive examination of financial management and cost structures in e-commerce, drawing on recent literature and empirical findings. It begins by introducing the unique financial characteristics of online retail and the importance of aligning financial strategy with marketing science insights. We then explore revenue recognition and financial reporting challenges specific to e-commerce, including the timing of revenue, principal-vs-agent considerations, and the treatment of returns and platform sales. Next, we delve into the cost accounting of digital business models, distinguishing fixed versus variable costs and analyzing key cost components such as technology infrastructure, platform fees, and logistics (fulfillment and shipping) expenses. We then examine profitability analysis in the online retail context, highlighting the use of contribution margins for decision-making, the calculation of customer lifetime value (CLV) for long-term profitability, and return on investment (ROI) metrics for evaluating marketing and operational initiatives. This section also examines current research findings and related research in financial management and marketing. The conclusion synthesizes these insights and highlights the need for holistic financial strategies that consider both cost efficiency and customer value to achieve sustainable online retail profitability.