How to manage your online store’s costs to keep it profitable

Calculating the total cost of ownership (TCO) for an online store goes well beyond just the platform's price. In a webinar hosted by PrestaShop and Marketing4eCommerce, three industry experts offered practical insights to help merchants anticipate actual costs and protect their margins. Esteban Martín (Channel Manager at PrestaShop), Antonio Roldán (CEO of INNPO), and Javier Galán (CEO of B2B Group) emphasized expense categories that many businesses often overlook, along with strategies aimed at enhancing profitability.

Antonio and Javier, both members of the PrestaShop Million Club, have over fifteen years of experience in distribution and online retail. Antonio leads INNPO and oversees Bateriasonline.com, a major player in energy storage products, batteries, and chargers. Javier manages three stores (20milproductos.com, Materialescolar.es, and Productospersonalizados.es), which together offer 40,000 SKUs and operate four warehouses coordinated through PrestaShop.

Open source and SaaS: looking past the entry price

The key distinction lies in the business models of each platform. SaaS solutions are appealing for their rapid deployment; however, they carry medium-term financial risks.

Antonio Roldán and Javier Galán pointed out the variable commissions applied on top of revenue (between 1.6% and 1.7% in additional fees). Additionally, there are costs for mandatory payment gateways, which can range from 2% to 2.7%. Altogether, the financial impact can reach 4% to 4.5% of sales with SaaS solutions.

PrestaShop, as an open-source solution, offers predictable and amortizable costs. The ability to choose payment gateways also enables merchants to optimize transaction fees according to their needs, which can significantly affect large volumes.

Calculating TCO over a four- to five-year horizon

All three speakers advocate evaluating TCO over a minimum of four to five years. This timeframe allows for the distribution of implementation costs and facilitates a fair comparison between CAPEX (initial investment) and OPEX (operational expenditures).

The calculation should include every cost component: initial development, hosting, modules and licenses, ongoing maintenance, and indirect expenses such as GDPR compliance, security, or translations.

Their proposed method is straightforward: sum all costs associated with launching and maintaining the store, divide the total by gross revenue, and then multiply by 100. This approach establishes a common basis for comparing solutions and forecasting budget trends.

Optimizing logistics based on the catalog

Logistics are just as crucial as the platform itself. Javier Galán estimates that his shipping costs account for approximately 11% of revenue. Antonio Roldán, who sells heavy batteries and energy equipment, experiences logistics costs ranging from 20% to 30%. This disparity underscores the need for logistics strategies to adapt to product categories.

Both merchants adhere to strict optimization guidelines. They limit stock to a maximum of two months, target an average turnover of 10–15 days, and employ algorithms to eliminate slow-moving items. Antonio also implements automatic markdowns to clear obsolete products and reduces SKUs with high return rates.

Optimizing marketing and acquisition costs

Marketing constitutes the third pillar of TCO. Javier Galán advises keeping acquisition costs below 8% of revenue after the initial launch phase. To achieve this, he leverages cross-selling: his third B2B merchandising store targets existing customers from his other sites.

Both experts emphasize the importance of assessing ROI before integrating any new tools. Adding features simply because they exist, without genuine usage, erodes margins without delivering value.

Cash-flow management: the top priority

Cash flow directly impacts TCO. Javier Galán outlined how to structure a P&L for ecommerce by clearly separating fixed and variable costs.

The priority is to maintain positive cash flow each month. To achieve this, he calculates the contribution margin (sales minus variable costs such as product, logistics, and financial charges) and ensures that it sufficiently covers fixed costs.

Antonio Roldán employs the same methodology. He reviews his P&L every two weeks or monthly and adjusts it for seasonality, staffing changes, and salary updates.

Takeaways

• Look beyond entry pricing when comparing SaaS and open source. Consider variable commissions and mandatory payment-gateway fees that can elevate SaaS costs to 4–4.5% of sales.
• Evaluate TCO over a four- to five-year horizon to fairly compare CAPEX and OPEX and smooth initial implementation costs.
• Include every cost line in the TCO model: development, hosting, modules, licenses, maintenance, GDPR compliance, security, translations, and any indirect operational costs.
• Use a simple comparison method: total costs ÷ gross revenue × 100 to establish a common baseline across platforms.
• Adapt logistics to the product catalog. Shipping costs vary significantly by category and can represent 11% to 30% of revenue depending on product weight and complexity.
• Enforce strict inventory discipline. Maintain stock under two months, aim for a 10–15 day turnover, and eliminate slow movers or high-return SKUs. Use price reductions to clear obsolete items.
• Keep marketing and acquisition costs below 8% of revenue after launch. Utilize cross-selling and your existing customer base before introducing new tools.
• Measure ROI before adopting any new software or feature. Avoid adding tools without clear, proven usage.
• Structure the ecommerce P&L with a clear separation of fixed and variable costs. Focus on contribution margin to ensure it covers fixed expenses.
• Prioritize maintaining positive cash flow monthly. Regularly review and update the P&L every two weeks or monthly to account for seasonality and staffing changes.
• Retain the core message: ecommerce profitability depends on disciplined cost control. Open source maintains control over critical levers, and operational rigor in logistics, catalog management, and cash flow drives sustainable growth.

The webinar reinforced a fundamental truth: success in ecommerce relies not only on revenue but also on meticulous cost control. Choosing an open-source platform like PrestaShop preserves control over strategic elements (payments, development, scalability) and avoids unilateral price increases. Optimizing logistics, rationalizing the catalog, and diligently monitoring cash flow provide the foundation for sustainable profitability. For merchants aiming for growth, these principles are essential for long-term survival and expansion.