It depends on whether this was situational pastoral counselling, which is part of his pastoral care of you, included in his position, or if it is on-going spiritual direction that is more elective in nature. If it is the latter, find out what spiritual directors are normally paid in your area, and offer to pay that. A one-time session or a few sessions within a short period for a specific purpose–a current bereavement, for instance, or discerning what action to take when confronted with a spouse’s infidelity–would usually be within his pastoral care of you.
Actually, if you ask your pastor or an associate pastor to become your spiritual director (and some priests find it problematic to serve as spiritual directors for their own parishioners, because the professional distance implied in the direction relationship could be hard to maintain within the social atmosphere of the parish), he may very well bring up the topic of compensation.
If the help you need or want goes beyond normal pastoral counselling, your pastor may suggest you find a professional counsellor or spiritual director to help you out. OTOH, if he knows you don’t have the means to get what you need, the question of money may never come up. He didn’t become a priest for the money that’s in it.