A participant tries to stay warm during the Macy's Thanksgiving Day Parade in Manhattan,New York, U.S., November 22, 2018. (Photo by Brendan McDermid/Reuters)

A gilrl plays games in a shopping mall in Beijing, China, 24 November 2021. Demographers in China have called for more efficient implementation of supportive measures to encourage births to address the country's dwindling population growth as country's birthrate last year was 8.52 births per thousand people, the lowest level since 1978, according China Statistical Yearbook 2021. (Photo by Wu Hong/EPA/EFE)

A guest dressed as a zombie attends the Middle East Film & Comic Con (MEFCC) in Gulf emirate of Dubai, United Arab Emirates, 11 April 2019. The event runs until 13 April 2019. (Photo by Ali Haider/EPA/EFE)

A large brawl breaks out as people leave the track after Sydney Racing at Rosehill Gardens on December 07, 2019 in Sydney, Australia. (Photo by Mark Evans/Getty Images)

A young sloth named Gloria, that was rescued after being stolen from the wild destined for trafficking, peeks out of the box it is being taken to be released at the city's Botanical Garden in Rio de Janeiro, Brazil, Monday, March 13, 2023. Gloria was cared for by the Free Life Institute NGO that rehabilitates injured wildlife found in the surrounding Rio area and returns them, when possible, back to the wild. Those that are too injured to be released are sent to other rehab centers or sanctuaries to live out their lives in protected environments. (Photo by Bruna Prado/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.

Linda Rooks from Yeovil in Somerset, a hostess at Whipsnade Zoo, wears “Tanga” a 7fy long python as a hat and scarf. (Photo by William Vanderson/Getty Images). 1965

A cosplayer poses for a photograph during the Comic Market 90 (Comiket) event in Tokyo Big Sight on August 12, 2016, Tokyo, Japan. Many manga and anime fans wearing cosplay lined up in the sun for the first day of Comiket. Comiket was established in 1975 and focuses on manga, anime, gaming and cosplay. Organizers expect more than 500,000 visitors to attend this year's summer event which runs for three days until August 14. (Photo by Aflo/Splash News)