Separate build costs from running costs
A useful estimate covers access to existing systems, data preparation, implementation, testing and handover. Running costs include model usage, hosting, monitoring and support. Ask what happens when usage doubles or an API changes.
Put a boundary around the pilot
Specify one process, representative test cases and an owner who can approve the result. Agree what is excluded. Compare the measured benefit with the full operating cost before extending the solution. A low demo price alone does not establish return on investment.