At my interview, I waited long before I was taken into the interview room. They do that for a reason; don't get impatient! Remember that most of the time managers are a whole lot more easy going than what they seem at first, so don't be afraid to ask questions, including salary or job description.
Interview questions [1]
Question 1
If they need you for a high traffic department, then expect to be asked technical questions about the products sold in that department.