Women dressed as a rabbit and a fox, who pose for pictures with tourists, walk in central Kiev, Ukraine April 4, 2018. (Photo by Gleb Garanich/Reuters)

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.

Honda Spanish rider Marc Marquez crashes with Aprilia Portuguese rider Miguel Oliveira during the MotoGP race of the Portuguese Grand Prix at the Algarve International Circuit in Portimao, on March 26, 2023. (Photo by Marcelo Del Pozo/Reuters)

Jamaica's Tissanna Hickling competes in the women's long jump qualification during the World Athletics Championships at the National Athletics Centre in Budapest on August 19, 2023. (Photo by Kirill Kudryavtsev/AFP Photo)

Chase Jackson, of the United States, competes during the women's shot put qualification at the 2024 Summer Olympics, Thursday, August 8, 2024, in Saint-Denis, France. (Photo by Ashley Landis/AP Photo)

In this Sunday, March 24, 2019, file photo, free skate pairs gold medalist Sui Wenjing and Han Cong of China perform during the gala exhibition for the ISU World Figure Skating Championships at Saitama Super Arena in Saitama, north of Tokyo. (Photo by Annice Lyn/AP Photo)

Alessandra Perilli, of San Marino, competes during the trap women's qualification at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Sunday, August 7, 2016. (Photo by Hassan Ammar/AP Photo)

2016 Rio Olympics, Judo, Final, Women, 48 kg Bronze Medal Contests, Carioca Arena 2, Rio de Janeiro, Brazil on August 6, 2016. Otgontsetseg Galbadrakh (KAZ) of Kazakhstan and Dayaris Mestre Alvarez (CUB) of Cuba react. (Photo by Kai Pfaffenbach/Reuters)