You cannot get an interview JUST by putting in an online application. You MUST make personal contact with a manager either in person or by phone. I had 3 interviews, 2 standing at the end of a checkout line and one in the manager's office. They asked very generic HR questions, and the interviews lasted less than 5 minutes.

Three rounds of interviews. If you're lucky, you'll do two rounds because two managers in the room are two interviews. Then the final interview is with the warehouse manager. Be on time; I cannot stress that enough, as Costco is a very time-sensitive type of position. You only have a three-minute grace period to clock in at your normal hours. Emphasize that you are very prompt and are ready to work through the probation period.