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 young vendor hawks food on a market in Kara in the state of Ogun, on September 23, 2015. Nigeria imposed tight movement restrictions in the restive northeast after Boko Haram bombings that killed more than 100 raised fears of fresh attacks over the Eid al-Adha festival. The military said the use of all vehicles would be banned throughout Borno state during the Muslim festival, which is known as Sallah in Nigeria and marked with two days' public holiday from Thursday. (Photo by Pius Utomi Ekpei/AFP Photo)

Various kinds of pumpkins, out of some 400 on display grown this season, are seen on sale at Franzlbauer farm in Hintersdorf, Austria, October 27, 2015. (Photo by Heinz-Peter Bader/Reuters)

An area of vegetation can be seen amongst drought effected farmland in South Australia, November 12, 2015. A pioneering Australian scheme to improve the management of water in the world's driest inhabited continent is facing its first real test as an intensifying El Nino threatens crops and builds tensions between farmers and environmentalists. An El Nino, a warming of sea-surface temperatures in the Pacific, is already causing drought and other extreme weather, affecting millions of people across parts of the world, and experts warn that the intensifying weather pattern could emerge as one of the strongest on record. (Photo by David Gray/Reuters)

In this photo taken on March 16, 2019, 13-year-old Reymark Cavesirano collects left over herring onboard a fishing boat anchored at the mouth of Manila Bay off Navotas City in suburban Manila. Cavesirano, a grade five student, paddles to the anchored fishing boats and helps crew clean their nets, and in exchange collects leftover herring still tangled in the nets. Across the Philippines, there are 5 million child labourers, aged between five and 17, many of them working in dangerous conditions. About 22 million people – a fifth of the population – live below the national poverty line. (Photo by Ted Aljibe/AFP Photo)

The silhouette of a woman is reflected in a puddle as she crosses a square in front of the Peter and Paul Cathedral in Saint Petersburg on March, 17, 2019. (Photo by Olga Maltseva/AFP Photo)

Joel said documenting the Kazakh nomad summer migration was really an epic journey – a time travel journey – and at the same time was possible to get an understanding of how the balance of nature is still possible in Altai Mountains, Mongolia, June 2015. (Photo by Joel Santos/Barcroft Images)

A small flock of birds seems to be giving an escort to an airliner on final approach to Reagan Washington National Airport in Arlington, Virginia on January 12, 2022. The scene took place over Gravelly Point which is an area within the National Park Service's George Washington Memorial Parkway. (Photo by Michael S. Williamson/The Washington Post)