According to Snopes.com, the scam promises users the coupon if they complete several surveys and share the post on Facebook.
During that process, users were also asked to provide personal details, such as their name, address and phone number.
On Tuesday, Costco posted to Facebook thanking fans and members to alerting them to the scam.
"While we love our fans and our members, this offer is a SCAM, and in no way affiliated with Costco. Thanks to our fans for letting us know about this recurring hoax!" the company' posted.
Costco is asking those who believe they have been targeted by phishing or scamming to contact firstname.lastname@example.org or to consider filing a report with the Federal Trade Comission.
The warehouse club chain also provided the following guidance:
-- Never respond to emails that cannot be verified.
-- Never provide personal information via e-mail.
-- Contact the business by using legitimate phone numbers to verify the request.
-- Enter websites using your browser and not by clicking on provided links.
-- Be cautious of any solicitation requesting that you deposit a check or pay a fee to collect a prize, get a job, or cover vaguely described "costs."