My Costco had one at $700, display model. Not quite $600, sadly. I asked the floor staff, the cashier, and the checkout manager if they price matched--showing them the $600 price tag posted here. Sadly, they do not. Prices vary from store to store and they mark down at their own discretion. But I still bought it. Haven't set it up yet, but 90 day return policy, 2 year warranty...this floor model is fine with me!
You can call Costcos in your area and give them the product number (657978) and they can check inventory. They won't have the marked down price in their database, but they have inventory count. But if they only have one or two at the location, odds are they have marked them down. They can also see if other nearby Costcos have stock. Hope that helps.