An empty Turcot Interchange is shown in Montreal, Saturday, January 9, 2021, as the Quebec government imposed a curfew to help stop the spread of COVID-19 starting at 8 p.m until 5 a.m and lasting until Feb. 8. (Photo by Graham Hughes/The Canadian Press via AP 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 woman, with her face covered with colored powders, dances during the Holi Festival of Colors in Lisbon, Sunday, September 15 2013. The festival, which is mainly celebrated during the Hindu spring festival Holi in some regions of India and Nepal, has become popular among people in other communities. (Photo by Francisco Seco/AP Photo)

Gorgeous galaxies and stunning stars make up this selection of pictures from the shortlisted entries for this year’s Insight Astronomy Photographer of the Year award. The winners will be announced on 15 September, and an exhibition of the winning images will be will be displayed in a free exhibition at the Royal Observatory Greenwich’s Astronomy Centre from 17 September. Here: “Seven Magic Points”. The rusty red swirls of the circular, iron sculpture Seven Magic Points in Brattebergan, Norway mirror the rippling aurora above. (Photo by Rune Engebø/Royal Observatory Greenwich’s Astronomy Photographer of the Year 2016/National Maritime Museum)

Pangolins in Crisis: Brent Stirton, South Africa; 1st place, Natural world and wildlife. “Pangolins are the world’s most illegally trafficked mammals, with an estimated one million trafficked to Asia in the last 10 years. Their scales are used in traditional Chinese and Vietnamese medicine, and their meat is sold as a high-priced delicacy. As a result, pangolins are listed as critically endangered and anyone who trades or consumes them is breaking the law. This body of work exposes the trade, while exploring aspects of illegality and celebrating the people who are trying to save these animals”. (Photo by Brent Stirton/Sony World Photography Awards 2020)

A cemetery worker dig new graves at the Xico cemetery on the outskirts of Mexico City, as the coronavirus disease (COVID-19) outbreak continues in Mexico, June 10, 2020. (Photo by Edgard Garrido/Reuters)

A farmer seen harvesting his crops while Mount Sinabung spewing out volcanic ash on July 4, 2017 in North Sumatera, Indonesia. The increased volume of lava dome that reaches one million eight hundred cubic meters, said volcanologist, through radio communications, do not dampen the activities of the people around sinabung, such as farming, harvesting their crops, picking up objects that are still left behind, or just take a picture while walking around near mount Sinabung. (Photo by Sabirin Manurung/Pacific Press/Barcroft Images)

In this Wednesday, November 15, 2017 photo, a woman poses for a selfie with the carcass of a humpback whale on Ipanema beach, in Rio de Janeiro, Brazil. Biologist Rafael Carvalho said the whale appears to have been dead for a few days. Authorities were urging beachgoers who had flocked to Ipanema on a national holiday to stay away from the animal. (Photo by Silvia Izquierdo/AP Photo)