Costco wine experts dish on their favorite picks and deals that you can only get at the warehouse chain

"The Kirkland Zinfandel is really good," Reyes said. "It's consistently a good value year after year."

You can buy Simi Chardonnay outside of Costco. But, according to Reyes, you'd be pressed to snag a better deal on the wine beyond the warehouse.

She said that at certain points in the year, the wine sells for $8.99 at Costco.

Cullen is a massive fan of Costco's signature champagne, which sells for $19.99.

"That's insane for real French champagne," he said.

Cullen particularly enjoys Spanish wines. He said that, generally speaking, Costco has an excellent selection of high-value Spanish wines.

"The Spanish wines at Costco across the board right now just seem to be really good buys," he said.

This high-end wine isn't exclusive to Costco. But, according to Cullen, you can pick up a bottle for far less at the warehouse chain. He described grabbing a 2013 vintage.

"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."

Cullen said that he went "bonkers" for the "phenomenal" Stonestreet Sonoma Street Chardonnay at Costco.

His only quibble was the warehouse's timing.

"They just put it out now," he said. "I was like, 'Oh man, this would've been awesome to have in the summertime.'"

Cullen described Kirkland Rioja as a "screaming buy."

"Any bottle of wine that's $7 is ridiculously inexpensive," Cullen said.

Along with the Kirkland Rioja, the Kirkland Cote due Rhone de Villages is one of Cullen's favorite Kirkland selections.

"You'd be lucky to get a grocery store apothic red blend for $7," Cullen said. "If you went to Total Wine and you walked in and said I want a Cote du Rhone de Villages wine you're easily starting at $15 to $25. You're getting that at a screaming deal. And all of the readers are loving that one, too."

Reyes said she "really likes" Kirkland Prosecco, and added that she recently gifted a bottle to a friend she was visiting in New York.

"I think it's a great place to buy more expensive wine," Cullen said, adding that the savings are magnified as you spend more.