Add the running costs specific to selling online: platform subscription fees, payment gateway charges (a percentage of each sale), and often apps or plugins for shipping, taxes, and marketing. These recur, so factor them into the true cost, not just the build.
The cheapest path is a hosted platform where the store software and security are handled for you. A custom store costs more but gives full control over the experience and how it integrates with your other systems. Pick based on scale and how unusual your needs are.
Updated July 2026