Costco doesnt sell refills, they sell complete blades by Goodyear that are utter garbage now. They used to be a single piece beam blade that were halfway decent, especially for price. Now they are a segmented blade with the same price. They streak and chatter within weeks.
Rad is right, go to any parts store - O Reilly. Advance, AutoZone, Pep Boys, etc and they almost always have a set on sale. Amazon does as well if you prefer online. You can go higher end like Bosch Micro Edge or just get something cheap and replace more often. I am just using cheap Trico Exact Fit blades and they're working well even with the really wet year we've been having.
2015 NVP SL - Silver, 20% tint, Bully Dog GT, AEM filter w/ snorkel mod, Topper Rack, Hankook AT-M tires. DRL delete, HID's
2015 XLR Hyperlite 27HFS Toy Hauler
Blue Ox Sway Pro
Me, wife, 3 kids and 2 big dogs!