When you charge for your time in every other circumstance and choose to give a few free hours for free because the customer isn't ready to pay - STOP. Don't do it.
This leads to a messy situation where expectations are confused, outcomes are unknown and people may be bamboozled about their roles and responsibilities. The outcomes become foggy leading to changing goal posts.
Work in this context leads to ineffectiveness. The change you are seeking won't manifest easily where boundaries aren't there to contain it. Boundaries guide us towards the change we seek. They allow for us to stage and measure success and cultivate a disciplined approach to change.
The price you charge for your time is primarily income yes - but more importantly it's a sign or symbol of the value you bring your clients. It enables a set of boundaries that contain the change you seek which then acts as a check/balance/measure to the ephemeral change you bring.