Unless you're selling something that needs no explanation (like, say, socks), you have to pay attention to your value adds - something a lot of retailers seem to have forgotten. As Don Tennant of ComputerWorld points out:

What killed Circuit City is precisely the same thing that killed CompUSA a year ago: Its only real value-add -- knowledgeable sales and support staff with the expertise to explain the technology to customers -- was long gone. Specialty stores like Circuit City lost their appeal when they stopped investing in proper hiring practices and training programs. There was no longer any reason to venture out to Circuit City for electronics and computer gadgets and peripherals when you could get the same merchandise, probably at lower prices, while you were at Wal-Mart buying underwear and razor blades.

That nickle you save in the expertise department could cost you your business. If people expect expertise to come with your product, then they need to actually find expertise.