Sometimes this is the most important selling feature of an organization.
Actually its nearly the ENTIRE face of a public organization. I don't have bazillions of dollars, experience, or wherewithall to have sold to 10,000 people or so like my competitors do.
So I offer one thing to set me apart from the whole pack of them, that is first class service. I customize the dealing with that person to their situation and issues, so beyond anything else, I get more and more buyer feedback increasing which goes hand in hand with profit.
The most important thing about any marketing effort is image. What image are you portraying if you bought stolen items? Definitely not a very cool one. And so by being thorough and conscientious about what you're doing and selling, you can automatically increase your reputation. Giving you something others don't have. Even the largest wholesalers who sell all their items on eBay, uBid, craiglist & anywhere else- Don't have a really stellar reputation at all.
So I work really hard to do one thing, match a good experience and get back positive response by offering assistance.