How Much Does a Custom Shopify/PrestaShop E-Commerce Site Cost?

An e-commerce site in 2026 isn't a number on a pricing page. I've worked with founders who thought they'd launch their store for 2,000 € and discovered the real bill six months later: between the Shopify subscription at 289 €/month on the Advanced plan and the transaction fees, or the custom PrestaShop quote that climbs from 3,500 € to 15,000 € before it even goes live. The price of an e-commerce site depends on what you sell, how you sell it, and above all on what nobody tells you in that first quote.

What pricing pages don't show you

Most online comparisons list the monthly subscriptions and stop there. According to the guide from francenum.gouv.fr, one small business in three still has no website at all. The ones that take the plunge quickly find out that the advertised price is only the tip of the iceberg.

The true cost of an e-commerce site breaks down into four blocks: the upfront investment (capex), the monthly recurring costs, the per-sale transaction costs, and ongoing evolutionary maintenance. Ignore a single one of these blocks and your math is off by several thousand euros over three years.

Why is the first quote always incomplete?

A French e-commerce agency quote typically covers the design, the integration and the initial development. It ranges between 4,500 and 40,000 € depending on complexity. What it almost always leaves out: the cost of third-party apps, the payment gateway fees, and the post-delivery maintenance. On Shopify, Kyle from the Shopify Mastery channel puts it well: the Basic plan at 25 €/month is just the starting point, and the real bill can reach several hundred euros a month once you add apps, themes and transaction fees.

The minimum budget to sell online in 2026 is 5,000 € all-in for the first year. Below that, you're making compromises that will cost more to fix than to plan for.

Shopify: what it really costs in 2026

Shopify wins people over with its simplicity. Three main plans structure the offer: Basic at 25 €/month, Shopify at 66 €/month, Advanced at 289 €/month (annual rates, excl. tax, June 2026). Hosting, SSL and CDN are included. For a standard store (fewer than 500 products, French market), the Basic plan is enough to get started.

What are Shopify's hidden costs?

The real trap is the layers that stack up. A premium theme costs between 150 and 400 € as a one-time purchase (free themes like Dawn work, but they limit customization). The apps add up fast: upsell, customer reviews, email marketing, abandoned cart recovery. Budget 30 to 150 €/month in apps for a serious store.

Transaction fees add another layer. If you don't use Shopify Payments, Shopify charges 0.5 to 2 % per sale on top of the gateway fees. On revenue of 10,000 €/month, that's 50 to 200 € in net fees, every single month. According to the comparison from Consumer Buddy, this is precisely the line item beginners underestimate the most.

Hiring a Shopify agency for an optimized, custom theme costs between 8,000 and 15,000 €. For a more ambitious project (marketplace, multi-currency, business integrations), agencies charge from 8,000 to 80,000 €.

Is Shopify right for every e-commerce project?

No. Shopify works as long as you stay inside its ecosystem. The moment you need a specific ERP connector, complex B2B pricing logic or a custom order workflow, you're boxed in by the platform's limits or by 200 €/month apps that do the job halfway. I see it on assignment: founders who choose Shopify for a non-standard business need end up migrating within 18 months, and the migration costs more than the right choice would have in the first place.

Custom PrestaShop: the investment and the recurring costs

PrestaShop is open source, so free to download. That's where the confusion ends. A custom PrestaShop project is budgeted in stackable blocks.

How does a custom PrestaShop budget break down?

The technical base (installation, configuration, standard theme) starts around 3,500 €. Design customization adds 500 to 2,000 €. Specific features (product configurator, complex discount rules, an ERP connector like Sage or Odoo) cost between 1,000 and 10,000 € per module. For an Enterprise project with multi-store and multi-language needs and a large catalog volume, the capex climbs past 60,000 €.

The recurring costs are often the forgotten line item. Hosting ranges from 5 to 500 €/month depending on load (an OVH VPS at 20 €/month is enough to start, but a dedicated server with CDN and high availability runs over 300 €). The SSL certificate costs 50 to 300 €/year (Let's Encrypt is free, but EV certificates for e-commerce are paid). Corrective maintenance and security updates represent 500 to 5,000 €/year, depending on whether you have an in-house dev or an agency contract.

According to the guide from codeur.com, the total cost of an e-commerce site ranges between 500 and 15,000 € in initial development. But that figure only covers the capex: add three years of recurring costs and the real budget doubles, even triples.

When does custom make sense?

Custom PrestaShop comes into its own when your business imposes management rules that Shopify can't absorb: tiered pricing with customer conditions, multi-warehouse stock management with allocation rules, specific ERP or WMS connectors, or sector-specific regulatory compliance. If your store sells dropshipped t-shirts, custom PrestaShop is pointless capex.

I recommend custom when I identify at least three connectors or business modules that don't exist out of the box. Below that threshold, Shopify covers the need with less friction, and the budget you save funds customer acquisition. If you're torn between hiring a dev to run PrestaShop or bringing in a senior dev on contract at $210/day, the 12-month math often tips toward the contract for a first e-commerce project.

The real comparison: total cost over 3 years

To settle it, I laid out the numbers in a realistic scenario: a store with 200 to 500 products, monthly revenue of 15,000 €, a need for customer reviews, email marketing and cart recovery. No ERP connector, no exotic business logic.

What's the minimum budget to sell online?

In this standard scenario, Shopify comes to ~10,300 € over three years versus ~12,900 € for custom PrestaShop. The 25 % gap closes the moment you add an ERP connector or an advanced pricing module, which makes the Shopify apps balloon (200 to 500 €/month for Shopify Plus features) while custom PrestaShop development is a one-time investment.

The tipping point happens around 20,000 € in monthly revenue with specific business needs. Below that, Shopify is simpler, lower-risk, and the founder keeps their energy for marketing. Above it, with connectors, custom pays back its capex in 18 months thanks to the transaction fees saved and the absence of recurring app subscriptions.

What an AI-augmented dev changes in the equation

According to the guide from fr.wix.com, custom development of an e-commerce site can exceed 100,000 € for large accounts. That figure assumes a traditional team: a project manager, two devs, an integrator, a tester. With an AI-augmented senior developer, the picture changes radically.

How does AI cut the cost of custom development?

A senior dev using Claude Code or Cursor can ship a custom PrestaShop theme and three business connectors in 4 to 6 weeks, where a classic team takes 10 to 12. I've staffed e-commerce projects where time-to-first-commit was under 48 hours, and the MVP was in production in less than 30 days.

The real lever isn't the daily rate, it's velocity. A dev at $210/day who ships in 6 weeks costs $6,300. An agency team at 800 €/day that ships in 12 weeks costs 48,000 €. The technical result is comparable, because AI absorbs the boilerplate, the unit tests and the documentation, while the senior dev focuses on architecture and business rules.

This approach makes custom PrestaShop accessible to budgets that would have been forced onto Shopify just two years ago. The question is no longer "can you afford custom?", but "do you have business rules that justify it?".

"Custom isn't justified by the number of products, but by the complexity of the business rules. Without an ERP connector, without specific pricing logic, Shopify does the job with three times less friction."

Vincent Roye, June 2026

The verdict is clear. For a standard store with no particular business constraints, Shopify remains the rational choice: live in a few days, maintenance included, a mature app ecosystem. The moment your business demands ERP connectors, per-customer pricing rules or a non-standard order workflow, custom PrestaShop with an AI-augmented senior dev becomes the most profitable path over three years. Don't pick your platform by technical affinity: lay out your three strongest business constraints, and the budget works itself out.