What an e-commerce platform really costs over three years

The licence is usually the smallest part of what an e-commerce platform costs. Over three years, a retailer turning over a few million pounds online will typically spend several hundred thousand pounds on the platform in total, and most of it goes on payment fees, the build, and the people who keep the site running and improving. Compare platforms on the monthly subscription and you are comparing the wrong number.

The right number is total cost of ownership: everything you pay, to everyone, because you chose that platform, over a period long enough to include a build and at least one round of upkeep. Three years is the sensible window.

This guide lists every cost line, shows a worked three-year comparison, and points out the costs that most often get left out of the business case.

The short version

• Budget across eight lines: licence, payment fees, apps or extensions, hosting, build, maintenance, agency support and your own team's time.
• Payment fees are usually the largest single line, and they barely differ between platforms, so do not let them dominate the choice.
• Hosted platforms such as Shopify turn most costs into predictable monthly bills. Open-source platforms such as Magento have no licence fee but higher build and upkeep costs.
• The costs people forget are migration, integrations, internal time and the second year's improvements.
• A cheap build on the wrong platform costs more than an expensive build on the right one, because you pay for it twice.

The eight cost lines

1. Licence or subscription

What you pay the platform vendor. On hosted platforms this is a monthly fee. At the time of writing (October 2026), Shopify's UK list prices are £25 a month for Basic, £65 for Grow and £344 for Advanced when billed monthly, with Plus from £1,800 a month on a three-year term. Magento Open Source has no licence fee. Adobe Commerce is licensed by quote, so get the figure in writing for your own sales volume.

2. Payment fees

A percentage of every sale plus a fixed amount per transaction. Shopify lists online card rates of 2% + 25p on Basic, falling to 1.5% + 25p on Advanced and 1.3% + 25p on Plus. If you use a payment provider other than Shopify's own, Shopify adds a fee of between 2% and 0.2% depending on plan. On open-source platforms you contract directly with a payment provider and negotiate the rate.

3. Apps and extensions

Reviews, search, subscriptions, loyalty, returns, email. On Shopify these are mostly monthly subscriptions, some priced by order volume, so they rise as you grow. On Magento, extensions are more often bought once with an annual renewal for updates, but each one has to be installed, tested and kept compatible through upgrades.

4. Hosting

Included on hosted platforms. On open-source platforms you pay for servers, a content delivery network, backups, monitoring and someone to manage them. Good hosting is not where to economise: a slow or unstable site costs sales every day.

5. Build

Design, development, data migration, integrations, testing and launch. This is the line with the widest range, because it depends on how much is bespoke. A theme-based Shopify store and a custom Magento build with an ERP integration are different projects by an order of magnitude.

6. Maintenance

Security patches, version upgrades, fixing things that break. Close to nothing on a hosted platform, where the vendor does it. A real and recurring cost on open source: Adobe supports each Magento release for three years, so every installation needs a planned upgrade within that window, plus patches in between.

7. Agency or retainer

Ongoing development, design and optimisation after launch. This is separate from maintenance. Maintenance keeps the site as it is. A retainer makes it better. Stores that budget nothing here stand still while competitors improve.

8. Your own team

The hours your staff spend managing the platform, the agency and the suppliers. Rarely costed, always real.

A worked three-year comparison

Take a UK retailer selling £3m a year online at a £60 average order, which is 50,000 orders a year, taking payments through the platform's own or a comparable card provider.

In the table below, the Shopify licence and payment lines are calculated from Shopify's published UK list prices at the time of writing (October 2026). Every other figure is an illustrative range based on the spread of projects we see. They are not vendor prices or quotes, and your own figures could sit outside them.

How the calculated lines work: Advanced billed yearly is £259 a month, so £9,324 over 36 months. Plus on a three-year term is £1,800 a month, so £64,800. Card fees on Advanced are 1.5% of £3m (£45,000) plus 25p on 50,000 orders (£12,500), which is £57,500 a year. On Plus the same sum at 1.3% is £51,500 a year. Adobe Commerce is left out because its licence is quoted individually. Add that quote to the Magento column to compare.

What the table tells you

• Payment fees are roughly a quarter to two thirds of the total. They are also the line that differs least between platforms. Negotiate them, but do not choose a platform on them unless your volume is high.
• The licence is small. Even on Plus it is a fifth of the three-year cost at most. The saving from a "free" platform is real but modest.
• The ranges overlap. A simple Magento build can cost less than an ambitious Plus one. What you ask the platform to do matters more than which platform it is.
• Magento's range is the widest. The top end is where complex requirements, heavy integrations and a neglected upgrade meet. The bottom end needs a disciplined team and a stable site.
• At this size Plus does not pay for itself on fees. It saves about £18,000 in card fees over three years and costs about £55,000 more in licence. The case would have to rest on features. Our guide to Shopify vs Shopify Plus shows where that changes.

The costs people forget

• Migration. Moving products, customers, order history and content, and setting up redirects so search rankings survive. See our replatforming guide.
• Integrations. Connecting stock, warehouse, accounts and marketplaces. Often the largest part of a build, and the connectors carry their own monthly fees. Our guide to e-commerce integrations covers what to expect.
• Running two platforms at once. During a move you pay for the old one until the new one is live, and usually a little longer.
• Content. New templates need new photography, copy and banners. Somebody has to produce them.
• App creep. Usage-based apps move up a pricing tier as orders grow. Review the list every quarter.
• International fees. Currency conversion, duties and tax services, and local payment methods all take a cut.
• Fraud and chargebacks. Losses, dispute fees and any fraud screening tool.
• Compliance. Accessibility, cookie consent and card security obligations all take time and sometimes tooling.
• Training and handover. Your team has to learn the new admin, and productivity dips for a few weeks.
• Year two. The launch is the start. Budget for testing and improvement, or the build depreciates from day one.

Common mistakes in the business case

• Comparing the subscription only. It is the easiest number to find and the least useful.
• Taking the lowest build quote. Low quotes leave out migration, integrations or testing. Ask each agency what is excluded.
• Assuming open source is cheap because it is free. Booths were paying for Magento's enterprise edition when the free one did the job, and moving them across produced a substantial annual saving. But the saving came from dropping an unused licence, not from open source costing nothing to run.
• Ignoring the exit. Ask what it costs to leave: contract terms, data export, and how much of the build could be reused.
• Costing the platform but not the return. A platform that costs £50,000 more over three years and lifts conversion by a few percent can be the cheaper choice. Put revenue in the model next to cost.

How we'd approach it

We build the three-year model with you before anyone talks about design. First we take your real figures: orders, average order value, payment mix, current app and hosting bills, and what you pay for development now. Then we price two or three realistic options on the eight lines above, using vendor quotes where they exist and marking clearly where a figure is an estimate.

We include the options we would not build ourselves, and the option of staying put. A well-kept store on its current platform, with money spent on conversion work and better integrations, often beats a move. If a move is right, the same model becomes the budget for the build, and we check actual costs against it each quarter. For help deciding between platforms once you know the numbers, see how to choose an e-commerce platform.

Questions we get asked

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