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 deserted alley in the ghost town of Apice, in the province of Benevento, southern Italy, 22 November 2016. After the Irpinia earthquake that took place in southern Italy on 23 November 1980, leaving at least 2,500 people dead, 8,000 injured and 250,000 homeless, the town in the heart of the Sannio area was evacuated and its residents moved into what has become the new Apice. Only recently the narrow streets and the tragically abandoned buildings have started, slowly, to repopulate. (Photo by Cesare Abbate/EPA)

An elephant calf yawns as mahouts paint elephants ahead of celebrations for the water festival of Songkran in Ayutthaya, Thailand on April 11, 2019. The annual elephant Songkran event is held to promote the tourism industry. Songkran Festival is held also to mark the Thai traditional New Year falling annually on 13 April, and it is celebrated with people splashing water and putting powder on each other faces as a symbolic sign of cleansing and washing away the sins from the past year. (Photo by Soe Zeya Tun/Reuters)

Kha Tu Ngoc rests in her two- square- meter house in Ho Chi Minh City on May 2, 2018. The “micro- house” dwellings are dotted throughout Vietnam' s bustling southern hub, occupied by families clinging to postage stamp- sized plots a city developing at breakneck pace. Tucked away in winding alleys, nestled under new condo developments or sandwiched between street food stalls and shops, the tiny houses are easily missed by the unattentive passerby. (Photo by Thanh Nguyen/AFP Photo)

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)