A prototype of a new nano spaceship is displayed during a press conference held by Israel's Space IL organisation on December 8, 2011 in Ehud, Israel. Israeli President Shimon Peres participated in the event unveiling Space IL's latest prototype nano spaceship with the aim of launching a Israeli robotic spacecraft that will land on the moon and raise funds for scientific education in Israel. (Photo by Ilia Yefimovich/Getty Images)

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.

Model Kendall Jenner presents a creation during the 2016 Victoria's Secret Fashion Show at the Grand Palais in Paris, France, November 30, 2016. The pulse-quickening, celebrity-filled catwalk event of the year: the Victoria's Secret fashion show takes place in Paris with performances from Lady Gaga and Bruno Mars. (Photo by Charles Platiau/Reuters)

An employe of Russian Space Training Center hangs out to dry space suits of Russian cosmonaut Anatoly Ivanishin, NASA's U.S. flight engineer Kathleen Rubins, and Japanese space agency's flight engineer Takuya Onishi, right, after their undergoing training near in Noginsk, 60 km (38 miles) east of Moscow, Russia, Wednesday, July 2, 2014. The training was intended to simulate the capsule landing on water. Russian cosmonaut Anatoly Ivanishin, Japanese space agency's flight engineer Takuya Onishi, and NASA's U.S. flight engineer Kathleen Rubins are being trained for a future mission to the International Space Station. (Photo by Alexander Zemlianichenko/AP Photo)

A dhobi, or a washerman washes cloths on the banks of the River Gomti in Lucknow, India, Saturday, September 12, 2020. Dhobis are traditional laundry workers who wash clothes by hand and dry them in the sun, an occupation which has been in existence for generations. Most cities in India have a Dhobi Ghat, or washermen's area, where the city's pile of clothes is laundered. This practice is still popular in India, despite of modern technology. Around 1,000 families work in Lucknow's Dhobi Ghat. However, in light of the novel coronavirus, their wages have decreased drastically. With each family earning around US$100-200 per month. (Photo by Rajesh Kumar Singh/AP Photo)

Houses near Taal Volcano's crater are seen buried in volcanic ash from the volcano's eruption on January 14, 2020 in Taal Volcano Island, Batangas province, Philippines. The Philippine Institute of Volcanology and Seismology raised the alert level to four out of five, warning that a hazardous eruption could take place anytime, as authorities have evacuated tens of thousands of people from the area. An estimated $10 million worth of crops and livestock have been damaged by the on-going eruption, according to the country's agriculture department. (Photo by Ezra Acayan/Getty Images)

Madame Tussauds's wax figure of Audrey Hepburn sits at an empty table to comply with coronavirus disease (COVID-19) social distancing requirements in a dining room at Peter Luger Steak House in Brooklyn, New York U.S., February 26, 2021. (Photo by Brendan McDermid/Reuters)

A newly hatched chick cuddles up to its mother at Santee Lakes near San Diego, California in May 2023. (Photo by Tammy Kokjohn/Solent News)