It will be easier to charge more for the same job when you're older. How do you make money on buying the mulch? Here's how. Find a local supplier. Use them and them exclusively. They'll have a price per yard for regular consumers and a price per yard for contractors. They give discounts to the contractors. Your customer doesn't know this. Charge them the customer price. It's not a HUGE difference, though. Usually $3-4 a yard.