Be candid with the interviewer about if you have or have had a Costco membership. If you currently shop at Costco, that's great! Be sure to mention how much you enjoy your membership and shopping at Costco! If you have had a Costco membership in the past, be sure to mention that you have shopped at Costco, and you really liked it! If you do not shop at Costco, that is okay too! Simply share that you do not currently shop at Costco, but you hear wonderful things about it all the time and look forward to being part of the team.