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.

Three young women preparing a guy. They are sitting him on a keg labelled “gun powder”. (Photo by Fox Photos/Getty Images). 1929

A motorist holds on to a post as she braves high winds and rain of Super Typhoon Meranti in Kaohsiung, southern Taiwan, 14 September 2016. The storm is the strongest recorded since Super Typhoon Haiyan developed in 2013. (Photo by Ritchie B. Tongo/EPA)

Convention goers dressed as bright colored Wookiees, a fictional species from the US epic space opera franchise Star Wars, prepare for a group photo outside the Comic Con 2016 in San Diego, California, USA, 22 July 2016. The San Diego Comic Con 2016 runs from 21 until 24 July. (Photo by David Maung/EPA)

James Brady and a police officer are seen lying on the ground after being shot while the suspect John Hinckley Jr. is apprehended,at right, moments after the attempted assassination of President Ronald Reagan, Washington, DC, March 30, 1981. (Photo by Dirck Halstead/Getty Images)

The Queen Elizabeth Tower (Big Ben) is reflected in a puddle as a cyclist rides by in London, on 27 June 2016. Britain began preparations to leave the European Union on Monday but said it would not be rushed into a quick exit, as markets plunged in the wake of a seismic referendum despite attempts to calm jitters. (Photo by Leon Neal/AFP Photo)

Ecuadorean spontaneous bullfighters participate in a popular bull festival called Las Canteras del Antisana at Pinantura village on the base of the Antisana volcano in Quito, November 28, 2015. (Photo by Guillermo Granja/Reuters)

Tokyo Rainbow Pride 2015, at Yoyogi park-Shibuya, on April 26, 2015. Some 3,000 lesbian, gay, bisexual and transgender people paraded through Tokyo’s Shibuya district Sunday afternoon to demonstrate their hope that Japanese society will continue to forge ahead with recent moves to embrace equality and diversity. In a nation where prejudice against sexual minorities persists, the annual Tokyo Rainbow Pride parade has sought to counter the trend by openly spotlighting LGBT residents and spreading their voices. But this year, LGBT participants and proponents seemed particularly joyous, emboldened by what they see as a blossoming of LGBT-friendly moves by municipalities and companies. (Photo by Yoshiaki Miura)