Everyone wants to get something for nothing - whether it's a lucky upgrade that means you can turn left when you get on a plane instead or heading off into the economy seats, or even getting a few extra features thrown in for free when you buy a new car.

As some of the sharpest businesses around, no-one understands this quite as well as casinos and that's why they all have a system that they call comps. It's short for "complimentary offers" and these are special treats specially designed to reward you for your loyalty to the casino in question. They're basically bonuses.

A man sleeps between tombstones in front of his single-room home on a hot night in the Cairo Necropolis, Egypt, October 13, 2015. In the sprawling Cairo Necropolis, known as the City of the Dead, life and death are side by side. Amid a housing crisis in Egypt, and with the population of greater Cairo estimated at about 20 million, people count themselves lucky to have a place to call home in the graveyards that date back hundreds of years. (Photo by Asmaa Waguih/Reuters)

A woman reacts as she poses with a man dressed up as the Star Wars character Chewbacca outside the Dolby Theatre, the site of the 88th Academy Awards in Hollywood, California February 26, 2016. (Photo by Adrees Latif/Reuters)

UK “Ex on the Beach” star Chloe Goodman rocks some serious sideboob in a slinky green outfit on a night out in London, England on September 13, 2016. (Photo by XposurePhotos.com)

Indian actress, singer and the winner of the Miss World 2000 pageant Priyanka Chopra starred as Victoria Leeds in the 2017 remake of “Baywatch”. (Photo by AP Photo/Paramount Pictures)

Bebe Rexha wears satin fuchsia suit while leaving The Tonight Show Starring Jimmy Fallon in New York City on December 20, 2018. (Photo by Felipe Ramales/Splash News and Pictures)

The 21-year-old UK Love Island’s star Rebecca Gormley stunned in a plunging crop top during a shopping trip in Newcastle, England on March 23, 2020. (Photo by Backgrid UK)

p*rn star Asa Akira models the Namilia collection at Pier 59 Studios during NYFW Fall/Winter 2020 on Sunday, February 9, 2020 in New York. (Photo by Charles Sykes/Invision/AP Photo)