The verdict in three sentences
A custom B2B e-commerce platform costs GBP 30k-80k in 2026 depending on features (per-account pricing, quotas, order approval), versus GBP 2k/month for Shopify Plus. ERP integration — essential to sync stock, prices and accounts — adds GBP 8k-20k. The payoff shows in the basket: trade buyers order around 25 % more self-serve than by phone.
SaaS B2B or custom: what you actually pay
SaaS (Shopify Plus, BigCommerce B2B) launches fast but bills monthly and takes a cut; custom costs more upfront but has no feature ceiling. 2026 order of magnitude for a London wholesaler.
| Item | Shopify Plus B2B | Custom |
|---|---|---|
| Setup | GBP 6k-12k | GBP 30k-80k |
| Subscription | GBP 2k/month | Hosting GBP 150-400/month |
| Platform commission | 0.15-0.25 % | 0 % |
| Per-account pricing | Native (B2B) | Unlimited custom |
| Quotas & order minimums | Limited | Full rules |
| Approval workflow | Basic | Multi-level |
| ERP integration | GBP 8k-15k | GBP 8k-20k |
The budget lines of a B2B quote
A serious quote breaks custom work down by module. Indicative 2026 split for a GBP 50k project.
| Module | Budget share | Range GBP |
|---|---|---|
| Catalogue & B2B product pages | 15 % | 6k-10k |
| Per-account pricing / tiers | 18 % | 7k-14k |
| Cart, quotes, minimums | 14 % | 5k-9k |
| Accounts & roles (buyer, approver) | 12 % | 4k-8k |
| ERP / stock integration | 22 % | 8k-20k |
| Payment & credit terms | 9 % | 3k-7k |
| Design, UAT, training | 10 % | 4k-7k |
Mini case study
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James, sales director of a catering-supplies wholesaler in London, takes 60 phone orders a day. He invests GBP 46k in a custom platform with ERP integration. Shifting 45 % of orders to self-serve frees up roughly 1.5 FTE (~GBP 52k/year loaded) and lifts his B2B basket by +25 %. The extra margin repays the build in 11 months.
FAQ
What does an entry-level B2B platform cost? A scoped project with catalogue, per-account pricing and payment starts around GBP 30k in 2026, before heavy ERP work.
Is Shopify Plus enough for B2B? Yes for simple pricing rules; once you have quotas, credit terms and complex approval workflows, custom becomes cheaper over 3 years despite its upfront cost.
Is ERP integration mandatory? Not technically, but without it you rekey stock and orders by hand. Budget GBP 8k-20k depending on the ERP.
What is the timeline? Allow 3-5 months for a full custom platform, 6-10 weeks for a Shopify Plus B2B base.
How much basket uplift? Self-serve trade buyers order around 25 % more than by phone because they see the full catalogue and volume discounts.
Let's scope your project. Tell us about your catalogue, your ERP and the number of trade accounts, and we will frame scope, an indicative budget and a timeline. 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.
