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.

Hollywood actress Malin Akerman helps King Digital Entertainment set the Guinness World Record for the World's Largest Hammock to celebrate the launch of its new game Paradise Bay on Wednesday, September 2, 2015, in Jersey City, N.J. (Photo by Charles Sykes/Invision for King World Entertainment/AP Images)

A man arrested for protesting over human rights abuses makes a court appearance in leg irons at the magistrates courts in Harare, Monday, September 14, 2020. Human rights defenders say it appears the government is using restrictions imposed to combat COVID-19 to suppress political criticism. Opposition officials, human rights groups and some analysts accuse Mnangagwa of abusing the rights of critics, using tactics as harsh as his predecessor, the late Robert Mugabe. (Photo by Tsvangirayi Mukwazhi/AP Photo)

Orphaned mountain gorilla, Ndakasi, lies in the arms of her caregiver, Andre Bauma, on September 21, 2021 shortly before her death, which the park confirmed on September 26. Mr Bauma and others at the Senkwekwe Mountain Gorilla Center had cared for Ndakasi and other orphans for 13 years. Ndakasi had suffered a prolonged illness prior to her death. This is the only mountain gorilla orphanage in the world and takes in mountain gorilla orphans who have lost their families to poaching or conflict. A number of the orphans here were rescued from sales by poachers in sting operations carried out by Congolese National Park Authority (ICCN) rangers. (Photo by Brent Stirton/Getty Images)

The Invasion. A quiet street in Macau. Modernization around is quickly changing the city, as documented by Paul Tsui. (Photo by Paul Tsui/National Geographic Travel Photographer of the Year Contest)

An employee of the National Park Service takes a selfie with President Barack Obama, left, in the background meeting with the crowd after a tour of Everglades National Park on Earth Day, Wednesday, April 22, 2015, in Florida. Obama used the visit to warn of the damage that climate change is already inflicting on the nation's environmental treasures. (Photo by Lynne Sladky/AP Photo)

Luling, Louisiana, US. New evidence contradicts previous claims of the relative safety of glyphosate, the world’s most widely used herbicide, which is manufactured here. It is often used in conjunction with seeds that have been genetically modified to tolerate its application, meaning that anyone consuming these crops is eating a genetically modified plant, and whatever residue of the pesticide that remains. (Photo by J. Henry Fair/Industrial Scars/Papadakis Publisher)

A woman clutches a teddy bear covered in red paint to symbolize blood during a government-approved, anti-violence rally held in the Kazakh city of Almaty on November 26, 2023. Organized by the New People youth movement, roughly 300 people took part. The rally was dubbed “Say No To The Animal World”, with organizers likening violent people to animals. (Photo by Petr Trotsenko/Radio Free Europe/Radio Liberty)