A young performer cries as she parades during the Bun Festival on Cheung Chau island in Hong Kong Tuesday, May 6, 2014. Bun Festival, the Taoist God of the Sea, is worshipped and evil spirits are believed to be scared away by loud gongs and drums during the procession. The celebration includes bun scrambling, parades, opera performances, and children dressed in colorful costumes. (Photo by Kin Cheung/AP Photo)

Bottles of vintage cognac, with a royal warrant stamp, are seen in storage inside Berry Bros and Rudd wine merchants in central London, Britain, August 21, 2015. Berry Bros. & Rudd, which started as grocers over 300 years ago in St. James's, central London, has two royal warrants. Every year Queen Elizabeth grants about 20 royal warrants, the gold emblem of the British monarchy, in a practice dating back to medieval times. The warrant holders can display the certificate and use the royal coat of arms in their marketing. The warrants lasting five years can help businesses break into new markets overseas, using their role as supplier to the royal family as a gauge of quality. On September 9, Queen Elizabeth will overtake Queen Victoria as Britain's longest-serving monarch. (Photo by Toby Melville/Reuters)

People walk down the street while Hurricane Matthew approaches in Port-au-Prince, Haiti October 3, 2016. (Photo by Carlos Garcia Rawlins/Reuters)

Geraldine Moodie overcame harsh conditions to become western Canada’s first professional female photographer, capturing beautiful images in the country’s most remote regions. An exhibition, “North of Ordinary: The Arctic Photographs of Geraldine and Douglas Moodie”, is at Glenbow, Calgary, 18 February – 10 September. Here: Inuit woman, Kootucktuck, in her beaded attigi. Fullerton Harbour, Nunavut, February 1905. (Photo by Geraldine Moodie/The Guardian)

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.

In this December 13, 2014 photo, Ricardo Alegria holds his donkeys by a leash as he yells to sell their milk in the streets of Santiago, Chile. Alegria, along with his brother Marco, has been selling fresh donkey milk for the past 25 years, and says it's recommended as a vitamin boost. Shot glass size cups of the drink sell for about $2 dollars. Half a liter, which is the most he says his donkeys can give in one day, sells for about $20 dollars. (Photo by Luis Hidalgo/AP Photo)

A truck driver naps under his truck at the fancy bazaar area during the twelve hours Assam bandh or strike in Guwahati, Assam, India, 23 October 2018. At least 46 organisations are observing a 12-hour bandh across the state to protest against the Centre's bid to clear the Citizenship (Amendment) Bill 2016, in the Winter Session of Parliament. (Photo by EPA/EFE/Stringer)

A glass skywalk in Wanyuan, Sichuan province, built along the side of a cliff, is the highest such skywalk anywhere in China on January 31, 2017. Some visitors have been proven to be terrified by the experience had to brace against the wall in fear. (Photo by Chinanew.com/AsiaWire)