The calendar still says summer, but the start of school -- and football season -- means we're in a time of transition. While we spent the summer stocking up on refreshing juice pops, T-shirts and pool toys, what we'll buy this fall is different.

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Costco also is in that in-between stage, still selling some of summer's staples while introducing merchandise for cooler weather and holidays ahead. From lingering school supplies to stuff for the final barbecues of the year to holiday treats, Costco is ready for the change of seasons.

As you start to stock your shelves for colder weather ahead, here are some great deals on the Costco shelves.

Hamburger Patties

"With summer winding down, it's a good time to get all the grilling in that you can," said Julie Ramhold, consumer analyst for DealNews.com. "And if you're planning to grill for the beginning of tailgate season, buying in bulk from Costco means having to buy less overall.

"Unless you have a  tried-and-true secret burger recipe and no other will do, the patties at Costco are solid picks that provide a tasty shortcut. A bag of 18 frozen patties will cost around $28 to $30, depending on whether you opt for Angus chuck or ground sirloin, which works out to about $1.56 to $1.67 each -- far better than what you'll spend at a standard grocery store."

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Gel Pens

"Back-to-school season is basically over, which means now's a good time to grab extra school supplies before they disappear from shelves," Ramhold said. "Costco has a few different types of gel pens that are perfect for students and office workers alike, including a UNI-BALL 12-pack for $12, a 20-pack of Pilot G2 pens for around $16, and a 40-count pack of Zebra retractable pens in various colors for around $10, so buying in bulk is definitely a good way to save."