Penelope Cruz attends the Palme d'Or Award Ceremony held at the Palais des Festivals during the 63rd Annual Cannes Film Festival on May 23, 2010 in Cannes, France. (Photo by Sean Gallup/Getty 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.

Anja Rubik poses as she arrives for the screening of the film “Dolor Y Gloria (Pain and Glory)” at the 72nd edition of the Cannes Film Festival in Cannes, southern France, on May 17, 2019. (Photo by Stephane Mahe/Reuters)

Model Bella Hadid poses for photographers at the photo call for the film “Pain and Glory” at the 72nd international film festival, Cannes, southern France, Friday, May 17, 2019. (Photo by Arthur Mola/Invision/AP Photo)

Star Wars collector James Burns, 44, poses for a photograph with some of his collection in London December 2, 2015. He said “I've met so many wonderful people, all over the world. It's a wonderful community of likeminded people with an interest in Star Wars. There's nothing else like it”. (Photo by Paul Hackett/Reuters)

A suspected street robber is arrested by a policeman after a brief chase in the streets, June 20, 2016, in Manila, Philippines. The president-elect of the Philippines, Rodrigo Duterte, declared a war on crime and drugs after sweeping an election on May 9 and has been living up to his nickname, “the punisher”. Philippine police have been conducting night raids almost on a daily basis and revived a curfew for minors that had not been enforced for years, rounding up minors drinking on the streets. (Photo by Dondi Tawatao/Getty Images)

A Pasola rider reacts after throwing his spear during the Pasola war festival at Ratenggaro village on March 22, 2014 in Sumba Island, Indonesia. The Pasola Festival is an important annual event to welcome the new harvest season, which coincides with the arrival of “Nyale” sea worms during February or March each year. Pasola, an ancient ritual fighting game, involves two teams of men on horseback charging towards each other while trying to hit their rivals with “pasol” javelins and avoid being hit themselves. (Photo by Ulet Ifansasti/Getty Images)