A young lady blows a balloon during a federal conference of the German Pirate Party (Piratenpartei) on December 3, 2011 in Offenbach, Germany. (Photo by Ralph Orlowski/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.

Valerie Hernandez Matias representing Puerto Rico poses in a swimsuit during the 54th Miss International beauty pageant in Tokyo November 11, 2014. Matias won the Miss International title. (Photo by Thomas Peter/Reuters)

Determination: silver. Adam Pelech (No 3) of the New York Islanders and Brian Boyle of the Florida Panthers crash the boards during their game at Barclays Center in New York. (Photo by Al Bello/Getty Images)

360Cities PRO member Andrew Bodrov has just published another stunning panorama stitched from images taken by the Curiosity Rover on Mars. Photo: “Mars Panorama – Curiosity Rover: Martian Solar Day 177” (Photo by NASA/JPL-Caltech/MSSS/Andrew Bodrov)

Sebastião Salgado is a Brazilian documentary photographer living in Paris. He has produced several books, and his work has been exhibited extensively around the world. His latest work, «Genesis», premieres at The Natural History Museum in London on April 11, on view through September 8, 2013. Photo: On South Georgia, a barren island in the far South Atlantic, a pair of southern elephant seal calves beckon before a colony of king penguins. “The male seals can grow to almost five tons,” says Salgado, “but these are just babies. This one looked at me with beautiful eyes”. (Photo by Sebastião Salgado/Amazonas/Contact Press Images)

A street in the Cuban capital, Havana, is home to 12 sets of twins, ranging from toddlers to senior citizens. Some say it could be something in the water. Others point to a tree with mystical significance for locals. And maybe it's just chance. Photo: In this September 29, 2013 photo, nine-year-old twin sisters Camila, left, and Carla Rodriguez pose for a portrait along their street in Havana, Cuba. 12 sets of twins live along two consecutive blocks in western Havana, ranging in age from newborns to senior citizens. “We love living on this block because we have twin friends”, said Carla. (Photo by Ramon Espinosa/AP Photo)

In this photo released by the Chin Human Rights Organization, fires burn in the town of Thantlang in Myanmar's northwestern state of Chin, on Friday October 29, 2021. More than 160 buildings in the town in the northwestern Myanmar, including three churches, have been destroyed by fire caused by shelling by government troops, local media and activists reported Saturday. (Photo by Chin Human Rights Organization via AP Photo)