What an online shop costs
For most UK retailers a Shopify-style platform is the right answer and a custom build would be money spent on the wrong thing. For a smaller number it genuinely is not. Here is how to tell which you are.
The main routes, UK 2026
| Route | Up front | Ongoing |
|---|---|---|
| Do it yourself on a platform | Your time | £19 – £289 a month plus apps and transaction fees |
| Agency-built on a platform | £2,500 – £15,000 | Platform fees plus any support retainer |
| Custom build | £8,000 – £40,000 + | Hosting, maintenance, security |
| Headless / composable | £100,000 + | A team to run it |
Ranges from UK platform and agency pricing, 2026.
Why the platform is usually right
A hosted platform handles the parts of selling online that are expensive to get wrong: payments, security, hosting, tax and uptime. Building those yourself is not a saving — it is volunteering to maintain them for ever.
The platform stops being the cheaper option in three situations: when transaction and app fees at your volume exceed the cost of running your own store; when you need integrations the platform does not support; or when the buying experience itself is the product — configurators, subscriptions with unusual rules, marketplaces.
Signs a custom shop may be worth it
- Your monthly platform, app and transaction fees are rising faster than revenue
- You maintain workarounds for things the platform cannot model
- Stock, orders or pricing must sync with systems the platform does not reach
- You sell something configured, bundled or recurring in a way the platform fights
- You are building a marketplace with many sellers, not a single shop
Questions people ask next
Is Shopify cheaper than a custom website?
To start, almost always. Over several years it depends on your volume, because platform and transaction fees grow with sales while a custom build is paid once and then maintained. Run both totals over three years before deciding.
What is a headless ecommerce build?
A setup where the shop you see is built separately from the software that manages products and orders. It is flexible and fast, and it is priced for businesses with a team to run it. Most do not need it.
Can I move from a platform to custom later?
Yes, and it is a common path: prove demand on a platform, then build custom once you know exactly what the platform cannot do for you. That knowledge is what makes the custom build worth the money.
Read next
What software costs in the UK
The ranges, what moves a project between them, and the costs nobody quotes.
What a booking system costs
When a £20-a-month tool is right, and when it is not.
How to compare development quotes
Why three quotes for one idea differ tenfold, and how to read them.
Platform or custom — for your shop specifically
Tell Moksy what you sell and how, and get a plan that says which route fits, what it will cost to build and run, and what would change the answer later.