Sell gift cards securely from Casey’s General Store with GCX's online gift card marketplace. Your Casey’s General Store gift card will be listed in front of the thousands of buyers perusing our gift card exchange. To sell Casey’s General Store gift cards quickly, set the price between 2% and 20% off the original amount. The asking price is up to you, but it really depends on the popularity of Casey’s General Store gift cards. Remember, you can adjust the selling price of your gift card at any time.