Proprietary ERP systems are dominated by license models priced per seat, module or transaction. That looks predictable, but it gets more expensive than planned as a company grows: new locations, employees, entities or modules all drive up running costs.

What matters for the decision is TCO, not the list price of the initial installation:

• One-time rollout costs (consulting, migration, training)
• Ongoing licenses and maintenance contracts
• Customizations and interfaces over the system’s lifecycle
• Internal or external operations

Open source ERP removes the user license. Budget shifts to processes, integration and operations. That moves the calculation, it does not eliminate it: hosting, support and further development still cost money.

Typical lock-in levers in license contracts: minimum terms, expensive module upgrades, and restricted export rights. Cross-check against vendor lock-in and exit strategy before signing.

For mid-sized companies, an ERP that grows with the business should not penalize growth. ERP for mid-sized companies and open source ERP provide the framework for the comparison.