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 relative of murdered prisoner, lies on a chair next to his coffin during a wake after a prison riot in the city of Altamira, Para state, Brazil on July 30, 2019. At least 57 prisoners were killed by other inmates during clashes between organized crime groups in the Altamira prison in northern Brazil Monday with 16 of the victims being decapitated, according to prison officials. (Photo by Bruno Kelly/Reuters)

Bella Hadid attends the “Tre Piani (Three Floors)” screening during the 74th annual Cannes Film Festival on July 11, 2021 in Cannes, France. (Photo by Lionel Hahn/Getty Images)

One of three young oriental small-clawed otters eats a meatball on June 18, 2015 in a zoo in Dresden, eastern Germany. The oriental small-clawed otter female Fussi gave birth to 3 healthy pups. Its pups now leave their burrow to explore the environment. (Photo by Arno Burgi/AFP Photo/DPA)

A pangolin carries its baby at a Bali zoo, Indonesia, Thursday, June 19, 2014. The pangolin baby was born on May 31. (Photo by Firdia Lisnawati/AP Photo)

A woman looks on while a horse-drawn carriage passes by Italian artist Emilio Ferro's artwork installation “Portal of Light” at the Giza pyramids necropolis during the second edition of the Art D’Égypte exhibition “Forever is Now” on October 27, 2022. (Photo by Khaled Desouki/AFP Photo)

A Siberian tiger gestures at the Siberian Tiger Park in Harbin, in China's northeastern Heilongjiang province, on January 6, 2023. (Photo by Hector Retamal/AFP Photo)

Japanese monkeys snuggle to keep warm at a zoo in Tonosho in Kagawa Prefecture, western Japan on January 24, 2023. (Photo by Kyodo Photo via Newscom/Alamy Live News)