Hollywood actress Malin Akerman helps King Digital Entertainment set the Guinness World Record for the World's Largest Hammock to celebrate the launch of its new game Paradise Bay on Wednesday, September 2, 2015, in Jersey City, N.J. (Photo by Charles Sykes/Invision for King World Entertainment/AP 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.

(L-R) American actress Joey King, English actor Aaron Taylor-Johnson and American actor Brian Tyree Henry attend the “Bullet Train” Photocall at The Corinthia Hotel on July 20, 2022 in London, England. (Photo by Gareth Cattermole/Getty Images)

Soldiers of the 70th division of the American 7th Army hold up a Nazi flag and a portrait of Adolf Hitler, taken during the World War II capture of Saarbrucken. (Photo by Horace Abrahams/Keystone/Getty Images). 22nd March 1945

More than 1,200 vintage posters that would send any movie buff into orbit were discovered in an Ohio garage, including the only known copy of an almost 7-foot-tall creation for the 1947 reissue of “Dracula” that could sell for $40,000. The Dallas-based Heritage Auctions in Dallas puts them all on the block March 22 and 23, including some rare specimens from the silent movie era. (Photo by Courtesy Heritage Auctions)

Aleksandra Miroslaw, of Poland, competes during the speed portion of the women's sport climbing final at the 2020 Summer Olympics, Friday, August 6, 2021, in Tokyo, Japan. (Photo by Tsuyoshi Ueda/Pool Photo via AP Photo)

A child enjoys a bath in a horse feeding tub near Settle, North Yorkshire, on Tuesday, May 31, 2022, as he and his family, from Accrington, Lancashire, head to Appleby, Cumbria, for the world-famous Appleby Horse Fair, which starts a week on Thursday, 9 June 2022. (Photo by Lorne Campbell/Guzelian)

Residents watch volcanic smoking and ashes rising from Mount Sinabung during an eruption in Karo, North Sumatra, Indonesia, February 24, 2016. Authorities have repeatedly called on local residents to remain patient in dealing with the impact of Sinabung's eruptions, which some experts have predicted will continue for five more years. (Photo by Xinhua/Barcroft Media)