Fishermen prepare marlin and sailfish, destined for Jakarta, for auction at a fish market in Tegal, Central Java November 26, 2014 in this photo taken by Antara Foto. (Photo by Oky Lukmansyah/Reuters/Antara Foto)

Nadeea Volianova the Russian Pop Star's bizarre, naked New Years “Art Installation” featuring an American flag, the named Putin and Trump in huge letters and the singer wearing a space helmet and not much else, Art Threat Gallery, Las Vegas, NV on December 29, 2016. (Photo by S_bukley/Splash News and Pictures)

A woman prays while touching the fingers of a Buddha statue during the annual Makha Bucha Day, which celebrates Buddha's teachings, in Ang Thong, Thailand February 11, 2017. (Photo by Jorge Silva/Reuters)

A model poses for a photographer backstage ahead of the Ferreira Couture catwalk show at Malta Fashion Week in Valletta, Malta on July 20, 2022. (Photo by Darrin Zammit Lupi/Reuters)

Mongolian herder, Khurelsukh, throws the carcass of a goat onto a heap as he struggles to deal with losing a quarter of his herd, on March 8, 2010 in Bayantsogt, Tuv province, Mongolia. (Photo by Paula Bronstein /Getty Images)

Artist Kong Ning wears a wedding dress made from respirators to highlight concerns about air quality and pollution in Beijing, China on December 1, 2015. (Photo by Luo Xiaoguang/Xinhua Press/Corbis)

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.

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)