Chateau de Beaucastel Châteauneuf-du-Pape
Cullen singled out the Chateau de Beaucastel Châteauneuf-du-Pape. He said that, while the wine is listed on Total Wines at around $100, you can snag a bottle at Costco for $70.
"Year to year it's consistent," he said. "It's a solid French Rhône blend. It's not cheap, but it's worth every penny."
Joseph Phelps Insignia
Cullen said he once bought the 2013 vintage of Joseph Phelps Insignia at Costco.
"That's normally $225 at most places," he said. "Costco usually has it at $199. I was able to get that for $179, which is a pretty good deal."
Generally speaking, the more expensive Spanish wines
Reyes said that Costco's selection of Spanish wines, especially the higher-end bottles, are "really good."
Cullen agreed, saying, "The Spanish wines at Costco across the board right now just seem to be really good buys."
More expensive Kirkland wines
Reyes told Business Insider that she tends to spring for the higher-end Kirkland wines when she's looking to splurge.
"Those are just already good values, and the higher up you go, the better value they are," she said.
Opus One
For shoppers looking for something extra special, Reyes mentioned that some clubs get a shipment of bottles from the uber-expensive Opus One Winery every year. She added that the bottles, which sell for somewhere around $300, are "hard to get" and sell out quickly.
Tip: If you've decided to spring for a pricey wine, still dig around in the bin
"Costco will put different vintages of the same wine in the same bin, at the same price," Cullen said.
He said he once found three different vintages of the same wine in a bin. So, if you've got your heart set on an expensive bottle, there's a possibility you'll be able to get an better vintage for the same price.