Ask a vendor what their ETRM costs and you will get a licence number. Ask an implementer and you will get a longer silence, because the honest answer is a multiple of that number, and the multiple depends on decisions you have not made yet. I have sat on both sides of these programmes. This essay is the budget conversation that should happen before the RFP, not after the first change order.
One rule before the line items: the licence is usually 15 to 30% of the total cost of getting live, and getting live is itself only part of the ten year bill. If your business case shows software as the biggest line, the business case is wrong.

