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)

A woman holding a dog walks out of a plane during a press event introducing Bark Air, an airline for dogs, at Republic Airport in East Farmingdale, New York on May 21, 2024. (Photo by Eduardo Munoz/Reuters)

A kid from Sichuan provice smokes at an assistance center February 23, 2005 in Shenzhen, Guangdong Province, China. The kids, ranging in age from 7 to 16, are temporary residents of the center, one of the institutions established by China's departments of civil affairs to help and administer beggars, vagrants and juvenile delinquents, after rescission of China's compulsory detainment and relocation system. (Photo by Cancan Chu/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.

A dog wearing ski goggles rides on the back of a man as they both stand in Times Square in New York, USA on January 25, 2021. (Photo by John Angelillo/UPI/Rex Features/Shutterstock)

A woman wearing a burqa begs on a street in Mazar-i-Sharif on December 22, 2021. (Photo by Mohd Rasfan/AFP Photo)

A woman dressed up for Halloween travels on a Metro train in São Paulo, Brazil on October 30, 2017. (Photo by Cris Faga/Rex Features/Shutterstock)

Venezuelan Hildemaro Ortiz relaxes inside of an abandoned bus in the border city of Pacaraima, Brazil on April 13, 2019. Ten destitute Venezuelan migrants who fled their country's crisis did not get far when they crossed into Brazil: they have been living for three months on an abandoned bus just across the border. (Photo by Pilar Olivares/Reuters)