Costco sells gift cards to some of your favorite places at a discount — and it's one of the most underutilized financial strategies available to any Costco member. The gift card arbitrage system is not a coupon hack, a promotional trick, or a limited-time opportunity. It is a permanent, structural feature of the Costco membership — available every day, year-round, through Costco.com — that allows members to effectively pay 75 to 85 cents for every dollar they spend at partici