It's no secret that Costco's main schtick is selling in bulk. They have fantastic products for very low prices. But unless you really want 20 pounds of onions when your recipe calls for half a cup, Costco is probably not your go-to store if you're planning on making a classic Thanksgiving dinner from scratch. There is, however, one thing that everyone (hosts and guests) should buy from Costco for Thanksgiving: the pumpkin pie.

Costco's pumpkin pie is a seasonal product, but it's a cult institution akin to Costco's food court pizza and $4.99 rotisserie chickens. Costco customers wait all year for pumpkin pies to go on sale, and during the off-season they write letters saying, "You should sell pumpkin pie all year."

What's So Great About Costco's Pumpkin Pie?

Costco's pumpkin pie is very good. The filling is sweet and smooth and a little fluffy, with distinct notes of cinnamon and nutmeg. Keeping a pie crust flaky under a layer of pumpkin is tricky, and a Costco pumpkin pie is always flaky. It's also enormous. A Costco pumpkin pie is 12 inches in diameter and weighs more than three-and-a-half pounds, but it costs a shockingly low $5.99 for the whole thing.

That price-to-size ratio is possible because Costco has pumpkin pie production down to a science. Every year, Costco makes more than six million pumpkin pies. More than 2.5 million pumpkin pies are sold at Costco in the week before Thanksgiving alone. (Don't worry — Costco says there is no chance of them running out of pies, even if you leave it until the last minute.)

Sometimes people on cooking forums complain about creating painstaking, labor-intensive, very expensive homemade pumpkin pies, and having their families prefer the Costco version.

Countless "copycat" recipes promise to duplicate the Costco pumpkin pie experience at home, but no recipe can beat Costco when it comes to price and convenience.

There are a lot of reasons to buy a Costco pumpkin pie — it's good, it's inexpensive, and it's enormous — but the most compelling reason to buy a Costco pumpkin pie is that if you bring a different pumpkin pie to Thanksgiving, chances are good that everybody will say: "Thank you for the pumpkin pie,; it's very good. Hey, you know who makes a great pumpkin pie? Costco!"

If you plan on having or bringing pumpkin pie at Thanksgiving, buy it from Costco. When it comes to price and value for the flavor, nothing else comes close.

Related: I Tried 6 Frozen Pumpkin Pies and Here's My Favorite

3 Other Things to Buy for Thanksgiving at Costco

While you're at Costco buying a pumpkin pie, you might also consider adding any of these items to your cart.

1. Kirkland Signature Asolo Prosecco Superiore DOCG, $7: At $6.99 a bottle, you can afford to serve sparkling wine all night.
2. King's Hawaiian Dinner Rolls, $6 for 24: These dinner rolls are sweet, buttery and delicious. They also freeze well, which is good because they're sold as two packs of 12, so you'll probably have a lot left over.
3. Another pie: The pumpkin pie is a must-buy, but a second pie adds variety. You'll have to decide for yourself if the second pie should be the pecan pie, which costs $13.99 for a 4.36-pound pie, or the legendary lattice apple pie, which is 12 inches in diameter and costs $9.99. Both are spectacular.

What Thanksgiving items do you usually get at Costco?