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2 min read
15.09.2026
ERP for a small business: stock and invoices, no bloat
A small business rarely needs a big ERP. Signs it is time, off-the-shelf software or custom modules, what drives the cost and where to start.
In short. A small business rarely needs a company-wide "big ERP". Usually stock, invoices and documents are enough — exactly where hours and money are being lost today. Off-the-shelf accounting software handles bookkeeping; custom modules handle the processes that don't fit into it.
ERP sounds like something for factories with hundreds of staff. In reality it's simply a system where stock, purchasing, invoices, commissions and documents live together, instead of in five spreadsheets and the owner's head.
Signs you need ERP
- Stock levels are unknown until someone goes and counts.
- Invoices and delivery notes are made by hand from a template and easy to mix up.
- Sales commissions are worked out in a spreadsheet at month end, with an argument every time.
- Sales and stock aren't connected: you sold something that's already gone.
- The owner builds the profit report from several sources.
Off-the-shelf software or custom modules
| Off-the-shelf accounting software | Custom modules | |
|---|---|---|
| Strength | Bookkeeping and legal reporting | Your business's own process |
| Weakness | Unusual processes need extra development | Doesn't replace accounting software |
| Best for | Standard retail, standard bookkeeping | Agencies, service businesses, made-to-order production |
| Integrations | From a list of supported apps | With your website, CRM, messaging — built for you |
The combination often works best: bookkeeping stays in the accounting software, while stock, deals and commissions live in your own system that exchanges data with it. Where invoicing software must be certified by the tax authority, as in Portugal, invoices stay in the certified tool and the rest connects to it.
What drives the cost
- Number of modules — stock, invoices, commissions and documents each add work.
- Integrations — every connection to accounting, a website or a messenger.
- Data migration — moving existing spreadsheets and records.
- Users and roles — who sees and edits what.
Where to start
- Write down where hours are lost. Stock, invoices, commissions or documents — pick one.
- Put a price on the mistakes. What does selling something out of stock, or a month of commission disputes, cost you?
- Start with one module and prove the value before automating the rest.
Example
For a real estate agency we built ERP modules on top of the CRM: deals, contracts and commissions in one chain. Commission is calculated from the deal automatically, and the owner sees what has been invoiced and what has been received.
What it costs with us
An ERP module from €500, a CRM starter from €1,500, and the initial business process map is a gift. Prices +VAT. More on the CRM and ERP development page, and on choosing between ready-made and custom in custom CRM or off-the-shelf.