Sculptures entitled “The Rising Tide” by British sculptor Jason deCaires Taylor are seen beside the River Thames in front of the Houses of Parliament and the London Eye ferris wheel in London, September 3, 2015. The representations of four horses and riders are fully visible at low tide but become immersed underwater twice a day as the Thames rises to reach full tide. The installation will be on display throughout September as part of the annual Totally Thames festival. (Photo by Toby Melville/Reuters)

Danila Shmelev, an artist from Moscow, Russia, works on a 3-D picture in Dubai, United Arab Emirates, Monday, February 27, 2017. Artists who focus on 3-D pictures have gathered in Dubai for the Dubai Canvas 3-D Art Festival, which runs from March 1 through March 7. (Photo by Jon Gambrell/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.

Britain's Catherine, Duchess of Cambridge plays a stroke of golf during a visit to meet young people supported by the Cheesy Waffles Project, a charity for children, young people and adults with additional needs across County Durham, at the Belmont Community Centre, in Durham, north east England on April 27, 2021. (Photo by Andy Commins/Pool via AFP Photo)

A Muslim boy prepares plates of food for an Iftar (breaking of fast) meal inside a mosque during the holy month of Ramadan in Ahmedabad, India, June 28, 2015. (Photo by Amit Dave/Reuters)

A man poses as “Lemongrab” from Adventure Time outside the MCM Comic Con at the Excel Centre in East London, October 25, 2014. (Photo by Andrew Winning/Reuters)

Elizabeth Nicolaou, a final year student with the Royal Academy of Dance, strikes a pose on April 28, 2022 near the Cutty Sark ship in Greenwich, London ahead of International Dance Day. First celebrated in 1982, International Dance Day has taken place every year since in anniversary celebration of the birth of Jean-Georges Noverre (1727-1810), considered the creator of modern ballet. (Photo by Guy Corbishley/Alamy Live News)

People cross a street against strong wind and heavy rainfall under the influence of Typhoon Haiyan, in Sanya, Hainan province November 10, 2013. One of the most powerful storms ever recorded killed at least 10,000 people in the central Philippines, a senior police official said on Sunday, with huge waves sweeping away entire coastal villages and devastating the region's main city. Despite weakening, the storm is likely to cause heavy rains, flooding, strong winds and mudslides as it makes its way north in the South China Sea. (Photo by Reuters/China Daily)