A cat sits in front of a retro car owned by retired mechanic Mikhail Krasinets at an open-air museum of Soviet-era vehicles in the village of Chernousovo, Tula region, Russia on September 27, 2018. In the remote village of Chernousovo, retired mechanic Mikhail Krasinets tends to more than 300 ramshackle, Soviet-era cars, remnants of a once vibrant auto industry that crumbled with the fall of the Soviet Union. (Photo by Maxim Shemetov/Reuters)

Man prepares wigs as he waits for customers in downtown Johannesburg, on August 5, 2014. Some estimates put Africa's dry hair industry at as much as $6 billion a year; Nigerian singer Muma Gee recently boasted that she spends 500,000 naira ($3,100) on a single hair piece made of 11 sets of human hair. (Photo by Siphiwe Sibeko/Reuters)

Katjinga, a Rhodesian ridgeback dog who lives on a 20-acre farm in Germany, adopted an abandoned pot-bellied piglet in August 2009. The tiny black piglet, named Paulinchen, had been so small at birth that her mother likely overlooked it. Katjinga's owner, Roland Adam, found the piglet alone and cold and brought it to his 8-year-old dog. (Photo by Fame Pictures)

The anthropometric record card of Sarah Giles, a servant who was convicted of stealing in 1897, on display making up part of a mosaic of cards on a table top during a press preview for the Crime Museum Uncovered exhibition at the Museum of London in the City of London, Wednesday, October 7, 2015. Drawn from Scotland Yard's private collection, the show charts more than a century of violence and suffering, from the murders of Jack the Ripper to IRA and al-Qaida bombings. But it also celebrates the brains, bravery and scientific advances that helped catch perpetrators and solve crimes. (Photo by Alastair Grant/AP Photo)

People collect water from shallow wells dug along the Shabelle River bed, which is dry due to drought in Somalia's Shabelle region, March 19, 2016. The cabinet ministers of the federal republic of Somalia have held on Thursday their weekly meeting in Mogadishu and discussed on the drought situation in parts of the country and its humanitarian consequences. Chaired by the acting PM and justice minister Abdullah Ahmed Jama (Ilka-Jir), the cabinet noted with deep concern the the prevailing situation in Somalia, with one of the worst ever drought in two decades. (Photo by Feisal Omar/Reuters)

The sun sets behind artist Luke Jerram's “Floating Earth” at Pennington Flash on November 22, 2021 in Wigan, England. The floating Earth will hover over Pennington Flash for 10 days from November 19, as part of a celebration of Wigan and Leigh's watercourses and is the first time one of Jerram's globes has been floated on an open expanse of water. (Photo by Christopher Furlong/Getty Images)

«Underwater». Laurie Simmons discovered this silicone sеx doll in a shop while on holiday in Japan and was immediately interested in the type of generic beauty their looks could add to her work. She went on to create the Love Doll series, in which she places silicone sеx dolls in positions that explore a woman’s interior life. (Photo by Laurie Simmons/Salon 94/The Guardian)

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.