A man fires a weapon as he dances during a traditional excursion near the western Saudi city of Taif, August 8, 2015. Saudis usually party in such excursions as they celebrate weddings or graduations. (Photo by Mohamed Al Hwaity/Reuters)

Drummers perform during rehearsals at the Bird's Nest National Stadium ahead of the IAAF Athletics World Championships in Beijing on August 20, 2015. The Athletics World Championships will be held at the stadium from August 22 to 30. (Photo by Greg Baker/AFP Photo)

Athletes in action during the international parachuting competition Mountain Gravity in Quinto, Switzerland, 27 August 2015. Some 200 participants from all over the world are expected to jump at the event running from 22 to 30 August 2015. (Photo by Samuel Golay/EPA)

A woman smokes marijuana during the annual 4/20 marijuana rally on Parliament Hill in Ottawa, Ontario, Canada, April 20, 2017. (Photo by Chris Wattie/Reuters)

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.

An animal advocate lays in fake blood in a replica of a meat package with a label that reads “meat” during a protest “The meat is murder” in the Bulgarian capital Sofia on May 8, 2016. (Photo by Nikolay Doychinov/AFP Photo)

Joanne the Scammer (L) and model Amber Rose attend the Amber Rose SlutWalk 2016 at Pershing Square on October 1, 2016 in Los Angeles, California. (Photo by Amanda Edwards/FilmMagic)

Performers take part in a rain soaked Notting Hill Carnival on August 25th, 2014 in London, England. Despite the bad weather over 1 million visitors are expected to attend the two-day event which is the largest of its kind in Europe. The event has taken place on the West London streets every August Bank Holiday weekend since 1964. (Photo by Mary Turner/Getty Images)