Tourists visit an art installation of colorful umbrellas on November 10, 2022 in Nanjing, Jiangsu Province of China. (Photo by VCG/VCG via Getty Images)

Marine One with US President Joe Biden onboard takes off from the South Lawn of the White House in Washington, DC, on April 16, 2024. Biden is travelling to Scranton, Pennsylvania. (Photo by Drew Angerer/AFP Photo)

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.

An Indian street vendor selling bananas naps on his fruit cart at the roadside in New Delhi on June 3, 2015. (Photo by Money Sharma/AFP Photo)

A woman reacts as she uses a selfie stick to take a photo of herself at Tiananmen Square in Beijing, China, Thursday, April 30, 2015. Selfie sticks are gaining popular in China, and many people are using them at popular tourist destinations. (Photo by Andy Wong/AP Photo)

Murad Khydyrov, horse and monkey trainer at the Great Moscow State Circus, and chimpanzee named Micky get ready for a rehearsal of the show called “History” as the circus prepares for its new season, which is to begin on September 19, in Moscow on September 17, 2020. (Photo by Natalia Kolesnikova/AFP Photo)

A woman jumps out of a street art object in the center of the Ukrainian capital of Kiev during a warm autumn day on September 25, 2020. (Photo by Sergei Supinsky/AFP Photo)

Noah, 10, cools himself off in his garden during hot weather in Hertford, Britain, June 25, 2020. The UK is experiencing a summer heatwave, with temperatures in many parts of the country expected to rise above 30°C and weather warnings in place for thunderstorms at the end of the week. (Photo by Andrew Couldridge/Reuters)