Get you a spreadsheet setup with all your expected expenses, and a projected client base/revenue and compare numbers. Many, and I say many, over-sell their products. Almost everybody does it. Some people over-sell to the point where there is no humanly possible way to profit off of a server if all users used what they were allotted. I would not do that, although you need to be competitive. Find an edge to be competitive, but don't cut yourself short, or your clients as they will ultimately decide if you stay in business.