The principles of sales vis a vis dealer cost vs buyer cost remain the same, whether it's a storefront operation selling small items or a different kind of business selling primarily mid- or high-priced items. I have worked the sort of retail that you seem to be saying I don't know anything about, and the same principles hold true there as anywhere else.

Edit: Oh, and I wonder - just how much economic study and deep market research have you done? What have you done to keep up with the changing nature of retail and service markets? How about the changing nature of product information and how it is both disseminated on the web and how that affects the knowledge of the buyer? Hell, how about the basic psychology of sales and what people buy and why? I