At participating Costco locations, sign up for a Costco 1-Year Gold Star Membership for $55 and get a $10 Costco Cash Card for free. Alternately, sign up for a Costco 1-Year Executive Membership for $110 and get a $20 Costco Cash Card for free. This offer is valid for non-members only for their first year of membership, and some exclusions may apply. Click here to find a location near you. Deal ends May 31.