The Cobra JoyRide car charger by Cobra Electronics is displayed during a press event at The Venetian for the 2012 International Consumer Electronics Show (CES) January 8, 2012 in Las Vegas, Nevada. The JoyRide works with Android phones and can automatically trigger preset phone functions like enabling GPS or disabling Wi-Fi with the press of a single button. It will be available for USD 39 in the second quarter of 2012. (Photo by Ethan Miller/Getty Images)

In this Saturday, March 3, 2018, photo, a contestant gets ready to throw a hatchet at a wooden bull's-eye at the Kick Axe Throwing venue in the Brooklyn borough of New York. Kick Axe Throwing is the first bar in New York City to pick up on a nationwide trend of ax throwing, a growing sport that some enthusiasts hope will take off the way bowling did in the last century. (Photo by Mary Altaffer/AP Photo)

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.

circa 1930: The neon illuminations of a wedding Chapel in Las Vegas.

Flamengo soccer fans cheer a goal scored by Gabriel against Argentina's River Plate in the Copa Libertadores final match, broadcast on a giant screen at a watch party at the Macarena Stadium, in Rio de Janeiro, Brazil, Saturday, November 23, 2019. The first single-match final will be played in front of more than 65,000 fans at Lima’s Monumental Stadium. The match was originally scheduled for Santiago’s National Stadium, but it was moved because of street protests in Chile. (Photo by Silvia Izquierdo/AP Photo)

United States's Jessie Diggins celebrates winning the cross-country ski, women's Tour de Ski overall standings, in Val di Fiemme, Italy, Sunday, January 7, 2024. (Photo by Alessandro Trovati/AP Photo)

Olympic medal winning twins Jessica (left) and Jennifer Gadirova celebrate their GCSE results at Aylesbury Vale Academy in Buckinghamshire, United Kingdom onThursday, August 12, 2021. (Photo by Steve Parsons/PA Images via Getty Images)