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.

Vintage wine bottles dated from 1946 lay down in the wine cellar of the Massandra winery near Yalta, 28 March 2014 (Yalta is a resort city on the north coast of the Black Sea in the Autonomous Republic of Crimea, a territory recognized by a majority of countries as part of Ukraine and incorporated by Russia as the Republic of Crimea). Massandra winery has one of the largest wine collections in the world. (Photo by Sergei Ilnitsky/EPA)

A robot named “Robovie-II”, developed by Japanese robotics research institution ATR, moves around at a grocery store during a shopping assisting experiment by utilizing the robot in an ubiquitous network technology platform in Kyoto, western Japan January 6, 2010. (Photo by Yuriko Nakao/Reuters)

A group of Ring Tailed Lemurs eat from a Thanksgiving spread at the San Francisco Zoo on November 23, 2011 in San Francisco, California. Fifteen lemurs at the San Francisco Zoo were treated to a Thanksgiving feast of green beans, a fruit salad made up of apples, bananas, grapes sweet potatoes and a turkey made out of monkey chow. (Photo by Justin Sullivan/Getty Images)

A model presents a creation for Kenzo by Japanese fashion designer Tomoaki Nagao aka Nigo during Kenzo fashion show at the North Bund Bay in Shanghai on July 28, 2023. (Photo by Jade Gao/AFP Photo)

A customer shops at an Alibaba rural service centre in Jinjia Village, Tonglu, Zhejiang province, China, July 20, 2015. E-commerce growth in the countryside now outpaces that in major cities, though fewer than one tenth of online purchases made on Alibaba platforms were shipped to rural areas in the first quarter of this year. Alibaba estimates the potential market at 460 billion yuan ($74 billion) by next year. (Photo by Aly Song/Reuters)

Children look at Hares and Ducks ahead of the Turkey and dressed poultry auction at Chelford Market, northern England December 22, 2014. (Photo by Phil Noble/Reuters)

In this Thursday, February 19, 2015 photo, participants at a seminar on edible insects taste a Cricket Consomme at Le Cordon Bleu cooking school in Bangkok, Thailand. A group of chefs and food scientists at the esteemed French school's branch in Bangkok spent the week simmering, sautéing and grilling insects to extract innovative flavors they say could open a new frontier for the world of gastronomy. (Photo by Sakchai Lalit/AP Photo)