Some professions qualify for credits when they sign up with Costco. If you're not one of them, find out how occasional new member promotions can lower your fee.

Right now, Costco is running a limited-time deal through Stack Social that’s so incredible, one shopper said it seemed “too good to be true.” While you’ll still have to shell out the typical $65 for a Gold Star membership, you’ll now receive a $45 Costco gift card with your purchase — bringing the ultimate cost of the membership down to just $20.

The warehouse store chain's Gold Star Membership normally retails for $65. For the next few weeks, shoppers can purchase a 12-month membership through affiliate marketer StackSocial and receive a $45 Costco gift card, effectively reducing their annual rate to $20 for their first year.

People who shop at Costco often enough are usually encouraged to upgrade from a basic membership to an Executive membership. The obvious downside of Costco's Executive membership is that it costs twice as much as a Gold Star membership -- $130 a year vs. $65.