Models wait backstage before the Heaven Gaia Autumn/Winter 2021 collection show by Xiong Ying during China Fashion Week in Beijing, China on March 25, 2021. (Photo by Tingshu Wang/Reuters)

People celebrate outside the Supreme Court, Friday, June 24, 2022, in Washington. The Supreme Court has ended constitutional protections for abortion that had been in place nearly 50 years, a decision by its conservative majority to overturn the court's landmark abortion cases. (Photo by Jacquelyn Martin/AP Photo)

Annabelle, 13, and her sister Estelle, 10, both artistic gymnasts from Borna, hang from the rings during their training, ahead of the Special Olympics World Games Berlin 2023, the world's largest sports movement for people with intellectual disabilities, at the Federal base for competitive gymnastic artistics in Chemnitz, Germany on May 6, 2023. (Photo by Annegret Hilse/Reuters)

English television presenter Maya Jama attends The Fashion Awards 2022 at the Royal Albert Hall on December 05, 2022 in London, England. (Photo by Backgrid UK)

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.

In this March 15, 2012 file photo, a Chinese woman poses for photos near a sculpture depicting a Chinese yuan note at an art district in Beijing, China. China devalued its tightly controlled currency on Tuesday, August 11,2015, following a slump in trade, triggering the yuan's biggest one-day decline in a decade. The central bank said the yuan's 1.3 percent fall was due to a change aimed at making its exchange rate controls more market-oriented. But any change raises the risk of tensions with China's trading partners. (Photo by Ng Han Guan/AP Photo)

A wax figure depicting Jennifer Lopez by wax museum Madame Tussauds dressed in a new set of clothes attracts the attention of pedestrians during a press event at a beach bar in Berlin,†Germany, August 21, 2015. (Photo by Jens Kalaene/EPA)

A Dancer, dressed with the traditional Yi costume, waits to perform at the Torch Festival, in Xichang, China's Sichuan province on July 27, 2016. As a result of fast urbanisation in the rural area of China Like Lienchang prefecture, the traditional costume is fading away for the Yi people in daily life. (Photo by Fred Dufour/AFP Photo)