Got this in my Amex Open website offers.

OFFER DETAILS

Get a 1x $25 statement credit by using your enrolled Card to spend $25+ on a qualifying purchase in-store at Costco by 8/15/2014. Get a Costco membership today!

TERMS
If you redeem this offer, your American Express Card Member status may be shared with Costco. Offer valid in store only at all US Costco Warehouse locations including Puerto Rico. Offer excludes gas, travel and online purchases. Costco membership required for purchases in-store at Costco, except for pharmacy transactions. $25 can include Costco membership purchase. Offer is non-transferable. Limit 1 statement credit per American Express online account. Enrollment is limited. If you order an item during the offer period but it is not sent to you until after 8/15/14, it may not count towards determining whether your purchase qualifies for the offer. Statement credit will appear on your billing statement within 90 days after 8/15/14, provided that American Express receives information from the merchant about your qualifying purchase. Statement credit may be reversed if qualifying purchase is returned/cancelled. If American Express does not receive information that identifies your transaction as qualifying for the offer, you will not receive the statement credit. POID: BE72:0001