11 little-known facts about Costco, where shoppers come for the pizza and stay for the diamonds

Flickr / Graeae Eye

Costco has fascinated shoppers and business experts alike, to the point where analysis of the company's strategy has become something of a cottage industry. The enigmatic warehouse store doesn't follow many of the traditional rules of retail.

Here are some lesser-known facts about the nation's largest wholesale club operator.

Related:11 Types of People Who Shouldn't Set Foot in Costco

Toilet paper is the best-selling item at Costco

Costco's most popular product: toilet paper. The chain sold more than 1 billion rolls worth some $400 million in 2015. In one clue to its importance, the toilet paper is often found deep in the store, so that budget-conscious customers have to pass many other tempting products on their way to stock up.

The aisles aren't labeled so shoppers will explore

Costco doesn't label its aisles for the same reason it places popular items at the back: As customers search the store to find what they came for, they see more items they want to put in their carts. Nevertheless, it should be easier to find items in the giant warehouses than in some other stores. Costco stores usually house about 4,000 products in an open layout while the average Walmart, for example, has about 100,000 products cluttering the aisles.

Related: 10 Surprising Things You Can Buy From Costco, Sam's, or BJ's

Chicken and hot dogs are cheap because they attract customers

Costco keeps its rotisserie chicken and hot dogs cheap because they are loss leaders. In other words, people come for the meat and stay for the flat-screen TVs. Chicken is one of those items placed strategically toward the back of the store so customers can be entranced by other offerings as they walk by. At $1.50, the hot-dog-and-drink combo has been the same price for years. For Costco, "traffic and long-term loyalty trump reactive price hikes," according to Bloomberg.