The verdict in three sentences
A custom B2B e-commerce platform costs between EUR 26,000 and 52,000 across six clear line items, with a 10-to-16-week timeline. Alongside it, a SaaS at ~EUR 2,300/month stacks ~EUR 83,000 in subscription alone over 3 years, before apps and transaction fees. The decision turns on 3-year TCO and on the business rules you absolutely must control.
Line-item breakdown
| Line item (2026 estimate, ex-tax) | Range | What it covers |
|---|---|---|
| Scoping / UX | EUR 3,500-7,000 | workshops, buyer journey, mockups |
| Catalog + search | EUR 6,000-11,000 | products, variants, filters, search engine |
| Pricing / accounts engine | EUR 5,000-9,000 | per-account grids, tiered discounts, roles |
| Payment + credit | EUR 3,000-6,000 | PSP, customer credit, ceiling blocking |
| ERP integration | EUR 4,000-8,000 | stock, prices, orders in real time |
| Acceptance + go-live | EUR 2,500-5,000 | testing, data migration, training |
| Total build | EUR 26,000-52,000 | complete deliverable |
Recurring costs and 3-year SaaS comparison
| Line item (2026, ex-tax) | Custom build | SaaS |
|---|---|---|
| Initial build | EUR 26,000-52,000 | EUR 6,000-12,000 |
| Subscription | EUR 0 | ~EUR 2,300/mo |
| B2B apps / add-ons | included | EUR 200-500/mo |
| Maintenance / changes | EUR 700-1,400/mo | partial |
| Hosting | EUR 150-400/mo | included |
| Cumulative 36-month | ~EUR 57,000-90,000 | ~EUR 95,000-110,000 |
SaaS is unbeatable in the first 12 months; custom regains the edge on the 3-year cumulative, especially at high order volume.
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Stefan, who runs a spare-parts wholesaler in Berlin, is undecided. On SaaS he would pay ~EUR 2,300/month plus EUR 350/month of apps = ~EUR 95,400 over 3 years. A build at EUR 38,000 plus EUR 1,100/month maintenance plus EUR 250/month hosting totals ~EUR 86,600 over the same period. The ~EUR 8,800 gap in favor of the build widens from year 4 (SaaS keeps running ~EUR 31,800/year, custom ~EUR 16,200/year). Decision: SaaS to move fast and test, build for the long haul and owned business rules.
FAQ
Why the gap between EUR 26,000 and 52,000? It depends on the number of pricing rules, catalog depth, and ERP-integration complexity. A tight perimeter pulls the budget down.
Is SaaS really costlier over time? Over 3 years, subscription alone stacks ~EUR 83,000. Beyond that, the gap widens each year in favor of custom, especially with paid apps added.
What does maintaining a build cost? Expect EUR 700-1,400/month maintenance plus EUR 150-400/month hosting. That is the price of evolution freedom and code ownership.
How long to deliver? 10-16 weeks for a full build including catalog, pricing, payment, credit, and ERP integration.
Can we start small and expand? Yes: we ship a core (catalog + ordering + pricing) first, then add credit, ERP, and advanced modules in batches. That smooths the investment.
Let's scope your project. Give us your catalog, pricing rules, and ERP, and we'll price each line item and compare it to SaaS over 3 years, indicative budget EUR 26,000-52,000. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.