The verdict in three sentences
For a Manchester building materials wholesaler with 3,500 trade customers and 12,000 SKUs, a custom B2B e-commerce platform costs 45,000 to 80,000 GBP and is delivered in 5 months, against a Shopify Plus B2B subscription at 2,300 USD a month plus integration. The decision turns on three things that define B2B: negotiated prices per account, credit limits and 30-day terms, ERP synchronisation. Aim for 25 % of orders online in year one: that is the threshold that truly frees the sales office from the phone.
Why the phone costs more than it seems
A builders' merchant in Greater Manchester typically handles 160 to 200 orders a day, more than 80 % of them by phone, email or at the trade counter. Each order goes through a sales office clerk who checks the customer's price, branch stock and authorised credit, then rekeys everything into the ERP.
| Indicator (2026 order of magnitude) | Phone order | Online B2B order |
|---|---|---|
| Sales office time per order | 6 to 8 min | 0.5 to 1 min (check) |
| Keying error rate | 2 to 3 % | 0.3 % |
| Average cost of an error (return, transport, credit note) | 70 to 105 GBP | 70 to 105 GBP |
| Availability for the customer | 7:30-18:00 | 24/7 |
| Average basket | 1,250 GBP | 1,380 to 1,460 GBP (suggestions, reorders) |
| Processing time | 2 to 4 h | Instant |
The trade customer wants to order in the evening, from site, and see their own price, not the list price. That is exactly what a B2C site cannot do without extra layers.
Custom or Shopify Plus B2B: the numbers
| Criterion | Shopify Plus B2B | Custom B2B platform |
|---|---|---|
| Initial cost | 18,000-30,000 GBP (integration, theme, ERP connector) | 45,000-80,000 GBP |
| Recurring cost | 2,300 USD/month, about 21,500 GBP/year, plus apps 250-700 GBP/month | Hosting and maintenance 6,000-10,000 GBP/year |
| Negotiated prices per account | Catalogues and price lists, limited on cascading discounts | Unlimited matrix: discounts by family, quantity, project |
| Credit limits and 30-day terms | Native payment terms, credit via third-party app | Credit read live from the ERP, automatic hold |
| ERP connection (Kerridge, Sage X3, Epicor) | Middleware connector 350-850 GBP/month | Direct API included |
| 12,000 SKUs with multiple units (pallet, m², linear metre) | Possible with metafields | Dedicated data model |
| 5-year cumulative cost | 150,000-200,000 GBP | 75,000-130,000 GBP |
| Timeline | 3 months | 5 months |
Shopify Plus remains a good choice if your catalogue is simple and your discounts standardised. Once every account has its own price matrix, delivery sites and a credit position monitored by finance, custom becomes cheaper over 5 years and more faithful to how you sell.
Features to demand in the specification
A successful merchant B2B portal comes down to trade details that professional buyers use every day.
| Feature | Customer use | Estimated impact |
|---|---|---|
| Net prices per account, visible after login | The contractor sees their negotiated price | No more "what's my price?" calls |
| Quick order by SKU or CSV upload | 40-line reorder in 2 minutes | +30 % of reorders online |
| Credit and invoices online | Tracking 30-day end-of-month terms | -20 % of calls to accounts |
| Multiple site addresses | Direct delivery to site | Fewer delivery errors |
| Stock by branch (Manchester, Salford, Stockport) | 2-hour counter collection | More click and collect |
| Multi-user accounts | Site manager orders, owner approves | Spending control on the customer side |
| Card or bank transfer for non-account customers | New customers without credit | Acquisition of small trades |
Mini case study
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Tom, sales director of a builders' merchant in Manchester, handles 40,000 orders a year. He chooses a custom platform at 62,000 GBP with 8,000 GBP of annual maintenance. With 25 % of orders online, i.e. 10,000 orders, he saves 6 minutes of sales office time per order: 1,000 hours at 32 GBP loaded, i.e. 32,000 GBP. Errors drop from 2.5 % to 0.3 % on those orders: 220 errors avoided at 85 GBP, i.e. 18,700 GBP. Annual gain: about 50,700 GBP, minus 8,000 GBP of maintenance, i.e. 42,700 GBP net. The project pays back in roughly 17 months, before counting the higher average basket.
FAQ
How long to reach 25 % of orders online?
Plan 9 to 12 months with an activation plan: counter staff training, sales reps contacting the first 300 accounts and a 1 to 2 % launch discount. Without support, the share often plateaus at 8-10 %.
Do we need to change ERP first?
No. The platform reads and writes to the existing ERP via API or file exchange. The connector usually accounts for 15 to 20 % of the budget, i.e. 9,000 to 14,000 GBP.
Will sales reps lose their commission?
The most common 2026 rule assigns online orders to the account's rep. Reps then become the portal's first promoters.
Which payment methods should we offer?
30-day end-of-month account terms remain the norm for credit customers. Add cards (about 1.5 %) and bank transfer for new customers, and consider a B2B buy-now-pay-later solution for baskets above 5,000 GBP.
Does e-invoicing change anything?
The UK has consulted on mandatory e-invoicing from 2029, while France starts in September 2026. Either way, the B2B platform must pass clean order data to the ERP that issues the invoice.
Let's scope your project. Send us your order volume, your ERP and your customer pricing structure: we price your B2B platform between 45,000 and 80,000 GBP, delivered in 5 months. 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.
