A Sri Lankan Christian girl wears a Santa hair band and a face mask as a precaution against the coronavirus as she arrives at a church to attend the Christmas mass in Colombo, Sri Lanka, Friday, December 25, 2020. (Photo by Eranga Jayawardena/AP Photo)

A couple buy a sugar-coated Chinese haw to a child at the Qianmen pedestrian shopping street, a popular tourist spot in Beijing, Tuesday, January 3, 2023. (Photo by Andy Wong/AP Photo)

People stand in the rain as they wait to enter the Martyrs' Mausoleum during a ceremony for Martyrs' Day in Yangon on July 19, 2020. Myanmar observed the 73rd anniversary of Martyrs' Day on July 19, marking the assassination of independence heroes including Aung San Suu Kyi's father, who helped end British colonial rule. (Photo by Sai Aung Main/AFP Photo)

A starling jealously guards a seed station in the back garden of the photographer’s Michigan home in January 2024. (Photo by Lisa Cavanary/Solent News)

Apple CEO Tim Cook discusses the new iPhone 6 and iPhone 6 plus on Tuesday, September 9, 2014, in Cupertino, Calif. The iPhone 6 will have a screen measuring 4.7 inches, while the iPhone 6 Plus will be 5.5 inches. (Photo by Marcio Jose Sanchez/AP 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.

This 1950s photo provided by the Estate of Vivian Maier and John Maloof Collection shows Maier in a self-portrait as she looks into a storefront wearing a hat in New York. New research about Maier shows the enigmatic Chicago nanny was obsessive about honing her skills as a photographer starting in 1950. (Photo by Vivian Maier/Estate of Vivian Maier and John Maloof Collection via AP Photo)