Mount Whaleback iron ore mine 23°21’32.3”S, 119°40’40.1”E. The Mount Whaleback Iron Ore Mine in the Pilbara region of Western Australia. Roughly 98% of the world’s mined iron ore is used to make steel and is thus a significant component in the construction of buildings, automobiles, and appliances such as refrigerators. (Photo by Daily Overview/DigitalGlobe, a Maxar Company)

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.

Replica of an old traditional Icelandic house from the 1800 with eruption of Iceland's Eyjafjallajökull volcano, 2013. (Photo by Ingólfur Bjargmundsson/Getty Images)

Passengers embrace each other at the entrance to Istanbul's Ataturk airport, early Wednesday, June 29, 2016 following their evacuation after a blast. Suspected Islamic State group extremists have hit the international terminal of Istanbul's Ataturk airport, killing dozens of people and wounding many others, Turkish officials said Tuesday. (Photo by Emrah Gurel/AP Photo)

A devoteetakes a holy dip in the River Ganges on Ganga Dussehra festival in Prayagraj, India, Tuesday, May 30, 2023. Hindus across the country celebrate Ganga Dussehra by worshiping the River Ganges, which is considered as the most sacred and the holiest river. (Photo by Rajesh Kumar Singh/AP Photo)

A man wades through flood waters carrying his grand daughter on his back following rains and floods during the monsoon season in Charsadda, Pakistan on August 28, 2022. (Photo by Fayaz AzizAziz/Reuters)

Granada’s International Poetry Festival is an extraordinary celebration of poetry that takes place across the entire city. For a week, every February, Granada is transformed into a virtual Capital of the World’s Poetry. Photo: A girl takes part in the “Burial of arrogance and haughtiness” carnival during the IX Poetry Festival in Granada, 45 km from Managua, Nicaragua on February 20, 2013. In this occasion the festival is dedicated to Nicaraguan poet Ernesto Cardenal. (Photo by Hector Retamal/AFP Photo)

A policeman kick in the door of a residence next to the Black Panther headquarters in New Orleans as they moved in following a shootout, September 15, 1970. Other heavily armed policemen stand at ready. (Photo by Jack Thornell/AP Photo)