A man dressed in red-white-and-blue sits on the curb during a protest against President-elect Donald Trump, Wednesday, November 9, 2016, in Seattle's Capitol Hill neighborhood. (Photo by Ted S. Warren/AP Photo)

Bill Wyatt, owner of the Y Que Trading Post in the Los Feliz neighborhood of Los Angeles, wears a Donald Trump face mask in his shop during the novel coronavirus COVID-19 pandemic on April 23, 2020. Wyatt has transformed his topical tee shirt business to a topical face mask business now called Y Que Mask and PPE Trading Post, since the start of the coronavirus crisis. According to Wyatt, the mask featuring Dr. Anthony Fauci is a best seller, as are masks with characters from the Netflix hit “Tiger King” and also popular internet memes. (Photo by Robyn Beck/AFP Photo)

“Senorita” – California-native fashion model Tiffany Keller heats up photographer Vladimir Marti’s lens for the April 2013 issue of Marie Claire Latin America. The dark-haired beauty poses in the city of San Miguel de Allende, Mexico, donning sultry styles from designer labels selected by fashion editor and stylist Gerard Angulo. (Photo by Vladimir Marti)

Fresh produce and baskets of fish surround a woman at the Siti Khadijah market in Kota Bharu, Malaysia. (Photo by Duratul Ain D.)

The “Assignments” exhibition is an annual chance to see the top images by UK photojournalists, as chosen by the British Press Photographers’ Association. Here: Wales’s Cory McKenna dominates Micol DiSegni during their fight at Cage Warriors 97 in Cardiff, 29 September 2018. (Photo by Chris Fairweather/Huw Evans Agency)

A view of the screen of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. Vending machines selling medical marijuana opened for business in Seattle on Tuesday, in what the company providing them billed as a first-in-the-state innovation that it expects to expand to other cities and states where pot is legal as medicine. (Photo by David Ryder/Reuters)

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.

A participant shows off a belt buckle during the 20th annual Seattle Invitationals, an amateur Elvis impersonator competition, in Seattle, Washington January 23, 2015. The event drew hundreds of spectators for 20 contestants at the Crocodile, a venue in Seattle's Belltown neighborhood. (Photo by David Ryder/Reuters)