How large a facility do you need?  What about racks, shelves and the like?  What sort of communications will you need?  What kind of advertising works?  How often?  How much?  How many employees should you  hire?  How do you train them?  How much should you pay them?  This list could go on forever and it seems to do so.  Most people buy an existing business because they recognize that they do not wish to spend the energy, time or money to "reinvent the wheel".  The person who can go in from "zero" and do all of this is the one I call the "entrepreneur".  Be sure you are ready for it before you begin!  At least part of the purchase price can be allocated to NOT having to spend the time, energy and money to get the business up and running.