I don't know about Kmart, but typically interviewers want to know why you want that particular job, why you think you would be good at it, and why you left, or are leaving your last job. I'm sure they will want to hear you just love working with people. What do you consider to be your biggest fault - and don't tell them you tend to work too hard. However you answer this question, remember that they will always be looking for trouble in that particular area.
Now, I don't suppose you consider this to be the job opportunity of your life, but they will take the interview seriously. For gosh sake, be on time and dress and groom a little bit better than you see on the sales floor.