As per Frequent Miler: Not valid for those with a current Costco membership or for memberships that expired after October 1, 2015.
Frequent Miler lists some additional bonuses as a part of the deal, as well as a cashback portal with 10% cashback ($5.50 discount):
Pay $55 and get a 1 year Gold Star membership plus:
- $20 Costco Cash Card
- Coupon for 72 AA Batteries ($18.99 value)
- Coupon for Food Court Pizza ($9.99 value)
- Coupon for Organic Tortilla Chips ($4.99 value)
- Coupon for $25 off $250 or more at Costco.com