You probably cannot sway someone who is looking only at final cost and not the value of what you are offering. When someone questions my course charges or tells me they can get a class cheaper elsewhere I usually briefly explain my course charges include all they supplies and books they need and that my course meets all the organizations guidelines. I follow up that they can certainly take a class with whomever they want, but to check that the lower cost includes their required book. Most end up registering for my class. Some don't and go elsewhere. If you discount to please everyone who asks you to do what you do for less you are devaluing what you do or provide.