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.

Model Heidi Klum and TV personality Nick Cannon speak onstage during Nickelodeon's 24th Annual Kids' Choice Awards at Galen Center on April 2, 2011 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

Afghan National Army (ANA) soldiers sit waiting to return their weapons after a day of traning at the Kabul Military Training Center (KMTC) October 3, 2010 in Kabul, Afghanistan. There are between 5,000 to 7,000 troops on the training facility in eight-week cycles trained by the coalition forces to ultimately take over the role of military operations in the country. (Photo by Paula Bronstein/Getty Images)

Face Off is an American reality television game show on the Syfy cable network in which a group of prosthetic makeup artists compete against each other to create prostheses such as those found in science fiction and horror films.

A boy rides on a snow wagon towed by a robot dressed as a Teddy bear, which only moves forward by moving its legs, during the Ice and snow carnival at Taoranting park in Beijing February 9, 2015. (Photo by Kim Kyung-Hoon/Reuters)

A man with henna-dyed hair rests on a road near the port area in Karachi, Pakistan on July 3, 2019. (Photo by Akhtar Soomro/Reuters)

Children jump into the water despite strong waves after a strong downpour at Manila's bay, Philippines, Wednesday, July 17, 2019. Schools in metropolitan Manila have been suspended as Tropical Storm Danas, locally named Falcon, continue to enhance the southwest monsoon as it maintains its strength bringing heavy rains over parts of Luzon and Visayas according to the Philippine Atmospheric Geophysical and Astronomical Services Administration. (Photo by Aaron Favila/AP Photo)

Indian Hindu sadhus (holy men) from the Juna Akhara take part in a religious procession towards Sangam area, during the first “royal entry” for the Kumbh Mela in Allahabad on December 25, 2018. (Photo by Sanjay Kanojia/AFP Photo)