Gloria Lincoln-Thompson carries her 9mm Smith & Wesson pistol in her waistband during a rally in support of the Michigan Open Carry gun law in Romulus, Michigan, in this April 27, 2014 file photo. (Photo by Rebecca Cook/Reuters)

A vendor prepares paan, a betel nut-based chewable stimulant at a flower market in Kolkata, India, January 18, 2016. (Photo by Rupak De Chowdhuri/Reuters)

A German fan cheers prior to the Group A match between Germany and Scotland at the Euro 2024 soccer tournament in Munich, Germany, Friday, June 14, 2024. (Photo by Antonio Calanni/AP Photo)

“We've reached 40km.” – Participants run at the 40km mark of the 2025 Chosun Ilbo Chuncheon Marathon, held in Chuncheon, Gangwon Province, South Korea on the afternoon of the October 26, 2025. (Photo by Park Seong-won)

Young dancers perform in a ballet adaptation of “Alice in Wonderland” during the Baghdad Ballet Academy's annual gala at Rasheed Theatre in Baghdad on August 29, 2025. (Photo by Ahmad Al-Rubaye/AFP Photo)

Finding just the right spot above the clouds at Camp 1 on Ama Dablam, Danuru Sherpa uses his iPhone to catch up with friends and family. Even at 18,500 feet (5,654 meters), climbers here can check their email and other dispatches from the world below. (Photo by Aaron Huey/National Geographic)

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.

Following a large air raid by German bombers, local people, coming out of their air raid shelters found a bus standing on end in a large crater, in Balham, London, October 15, 1940. (Photo by AP Photo)