Tim Klingender, Director of Aboriginal Art at Sotheby's hangs the painting “Emu Corroboree Man” by Clifford Possum Tjapaltjarri before a record auction of Aboriginal Art July 14, 2005 in Sydney, Australia. The painting is expected to fetch AUD 150,000 – 250,000 (USD 120,000 – 200,000). Sotheby's unveiled a selection of Aboriginal art and artifacts after a tour of New York and London, which will go to auction in Melbourne July 25 2005. The total pre-sales estimate of the collection is AUD 6 million – 8.5 million (USD 5 million – 7 million). (Photo by Ian Waldie/Getty Images)

Sushi chef Mitsuru Tamura uses a radiation detector on seafood before it is prepared in Manhattan's Sushi Yasuda restaurant April 8, 2011 in New York City. The restaurant has begun using the detector as a precautionary measure due to consumer concerns over possible radiation contamination in seafood from the nuclear emergency in Japan. Health officials believe contamination is unlikely to threaten the food supply chain and none has been found in this restaurant. (Photo by Mario Tama/Getty Images)

A David Cameron look-alike poses with a polar bear model outside the Houses of Parliament as part of a Greenpeace protest on May 13, 2011 in London, England. The environmental charity Greenpeace arranged the protest to highlight the first anniversary of David Cameron’s speech when he pledged to make his new government the greenest ever. In April 2006 Mr Cameron traveled by huskie-drawn sledge when he visited the island of Svalbard in Norway to witness the effects of climate change. (Photo by Oli Scarff/Getty Images)

A woman is cooled down with a watering can as she sunbathes using insulating tape, at a beauty center in Belo Horizonte, Brazil, on December 21, 2017. Brazilian women take advantage of the beginning of the summer to sunbathe using the new national trend: natural tanning with insulating tape. Instead of using tiny bikinis on the beach, women avoid being bothered or stalked by getting taped in the shape of them, and lay in the sun over rooftops to enjoy the morning sun and get the perfect “marquinha” tan lines. (Photo by Douglas Magno/AFP 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.

A chained male monkey in a costume and wearing a toy mask performs at a street in Depok, West Java, Indonesia, 30 September 2021. A performing monkey in a street, known as “Topeng Monyet” (lit. Monkey Mask), is a popular form of cheap entertainment in Indonesia, especially on the island of Java. (Photo by Adi Weda/EPA/EFE)

A girl rides on a train as she takes part in the first edition of the No Pants Subway Ride in Bucharest, Romania, Sunday, January 11, 2015. The No Pants Subway Ride is an annual which was started in 2002 by Improv Everywhere in New York, the goal is for riders to get on the subway train dressed in normal winter clothes without pants and keep a straight face. (Photo by Vadim Ghirda/AP Photo)

A woman poses for a photograph with light sculptures depicting animals that make up the twelve animals of the zodiac during a photocall to promote the Magical Lantern Festival at Chiswick House Gardens in west London on January 29, 2016. The festival, to celebrate Chinese New Year 2016 – the Year of the Monkey, uses more than 50 hand-sculpted lanterns and is set to run from Febuary 3 to March 6, 2016. (Photo by Justin Tallis/AFP Photo)