In this February 20, 2018 photo, fair vendor Noelia Flores holds up a black backdrop behind a small statue of an “Ekeko”, the god of prosperity, for a portrait at her booth during the annual Alasita Fair in La Paz, Bolivia. Every year, thousands of Bolivians head to the feast of Alasitas that is held in his honor to buy miniature cars, houses and toy dollar bills symbolizing their dreams of prosperity. (Photo by Juan Karita/AP Photo)

A protester sprays paint on the window of a bank during a rally against Expo 2015 in Milan, Italy, April 30, 2015. The Milan Expo will open in the city on May 1. Officials are counting on some 20 million visitors to the six month-long exhibition of products and technologies from around the world. (Photo by Stefano Rellandini/Reuters)

In this picture taken on July 10, 2023, women belonging to the “Meira Paibis”, a group of women representing Meitei society, hold torches during a demonstation demanding for the restoration of peace in India's north-eastern Manipur state in Imphal, following ongoing ethnic violence in Manipur. (Photo by AFP Photo/Stringer)

A woman dressed in traditional attire participates in a procession to mark Gudi Padwa or the Marathi New Year in Mumbai, India, Tuesday, April 9, 2024. (Photo by Rajanish Kakade/AP Photo)

Marine One with US President Joe Biden onboard takes off from the South Lawn of the White House in Washington, DC, on April 16, 2024. Biden is travelling to Scranton, Pennsylvania. (Photo by Drew Angerer/AFP Photo)

A woman holding a dog walks out of a plane during a press event introducing Bark Air, an airline for dogs, at Republic Airport in East Farmingdale, New York on May 21, 2024. (Photo by Eduardo Munoz/Reuters)

A kid from Sichuan provice smokes at an assistance center February 23, 2005 in Shenzhen, Guangdong Province, China. The kids, ranging in age from 7 to 16, are temporary residents of the center, one of the institutions established by China's departments of civil affairs to help and administer beggars, vagrants and juvenile delinquents, after rescission of China's compulsory detainment and relocation system. (Photo by Cancan Chu/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.