Though ill advised by task force, I use the method of doubling the cost of mowing for leaf mulching and dispersion throughout the yard using gator blades. When asked to actually remove leaves(which is rare) from the property I charge by the amount of leaves collected. How much that you charge is up to you on your expenses and the amount of profit you look to make of the job. I think you're actually fishing for numbers but those numbers are up to you.