Spectators await the start of a cinema screening at a Kinostar De Lux Multiplex in the Moscow suburb of Khimki, December 7, 2014. Furniture retailer IKEA has converted one of the cinema halls, completely replacing standard seats with their furniture, according to local media. There are 17 double beds fitted in the hall, which was renamed to “It wakes love”. (Photo by Sergei Karpukhin/Reuters)

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.

A fisherman boats in Chao Lake where thick cyanobacteria gather on the surface on August 5, 2015 in Chaohu, Anhui Province of China. As high temperature came in summar, part of water in Anhui Province's Chao Lake breeds large tracts of cyanobacteria which not only brought pollution to sense of smell, but also affected people's life. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

In this January 29, 2017 photo, musicians perform for dancers on the shores of Lake Titicaca, as they practice before their presentation for the Virgin of Candelaria celebrations in Puno, Peru. Dancers in colorful masks and elaborate costume celebrate the Virgin of Candelaria, patron saint of communities along the shore of Lake Titicaca, in what's considered the largest Catholic festival in the Andes. (Photo by Rodrigo Abd/AP Photo)

A picture taken on October 5, 2018, shows a general view of Migingo island which is densely populated by residents fishing mainly for Nile perch in Lake Victoria, the continent's largest lake, on the border of Uganda and Kenya. More than 500 people live on the island, which is barely 2,000-square-metres. (Photo by Yasuyoshi Chiba/AFP Photo)

A train drives along a field at a salt production site at the Sasyk-Sivash lake near the city of Yevpatoria, Crimea, November 14, 2017. A saltwater lagoon known as Lake Sasyk-Sivash on Ukraine's Crimea peninsula is the source of a rare resource: pink salt. The mineral is tinted by tiny algae that produce the pigment beta-carotene. Each autumn, seasonal workers collect thousands of tons of pink salt for processing and export. (Photo by Pavel Rebrov/Reuters)

Flames from the Jerusalem Fire erupt in Lake County, California August 12, 2015. The wildfire running rampant through drought-parched vegetation in northern California grew by several thousand acres overnight into Wednesday, as firefighters worked to stop the flames from spreading toward communities. (Photo by Robert Galbraith/Reuters)

Luxury buildings are reflected in front of houses at a lake dwelling also known as or palafitte or “Palafito” in Recife, Brazil, March 1, 2016. Zika has spread most rapidly in the urban squalor of Brazil's northeastern coastal cities like Recife. (Photo by Ueslei Marcelino/Reuters)