A face mask is placed on one of the 'Three business men who brought lunch' statues on Swanston street on March 29, 2020 in Melbourne, Australia. All international arrivals into Australia from midnight on Saturday will be placed into mandatory quarantine in hotels for 14 days as the Federal Government increases restrictions to stop the spread of COVID-19. (Photo by Asanka Ratnayake/Getty Images)

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.

Two drivers get into a fight while waiting in line at a gas station amid fuel shortages in Knightdale, North Carolina, May 10, 2021. (Photo by @shaaddeez/Instagram via Reuters)

Mulan Jamilah, a 6-year-old Bengal tiger, kisses caretaker Abdullah Sholeh, 33, in the garden beside their home on January 20, 2014 in Malang, Indonesia.

An Afghan hunter shoots at a duck in Laghman province, Afghanistan on May 30, 2018. (Photo by Reuters/Parwiz)

Fighters Holly “The Lotus” Mei (L) and Teri “Feisty Fists” London train for the upcoming 'Lingerie Fighting Championships 22: Costume Brawl I' at DXG Self Defense on October 25, 2016 in Las Vegas, Nevada. The event is scheduled to feature eight bouts at 4 Bears Casino & Lodge on October 29, 2016 in New Town, North Dakota. (Photo by Ethan Miller/Getty Images)

Trees grow through the windshield of a 1937 Chrysler Imperial as it sits at Old Car City, the world's largest known classic car junkyard Thursday, July 16, 2015, in White, Ga. Over 4,000 classic cars decorate 32 acres of forest which have been turned into a junkyard museum by owner Walter Dean Lewis. The two grew up playing in the cars on the lot which started as a general store selling auto parts in 1931 by Lewis' parents. Lewis stopped selling parts about six years ago when he realized he could sustain the business more as a museum, charging $15 for visitors just looking, and $25 for photographers. Many of the cars have never moved in over 30 years and in some cases, trees now grow through them, even lifting some off the ground. (Photo by David Goldman/AP Photo)

Tea garden workers carry sacks of tea leaves at Fatikchera tea garden estate on the outskirts of Agartala, India, May 10, 2016. (Photo by Jayanta Dey/Reuters)