Zombie Punk stands for a photo during the International tattoo convention at Tobacco Dock in east London, Friday, September 27, 2019. (Photo by Aaron Chown/PA Wire Press Association 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.

Rachel Hollon of Los Angeles was body painted as Harley Quinn at Comic-Con International in San Diego, USA on Jule 20, 2017. (Photo by K.C. Alfred/San Diego Union-Tribune via ZUMA Press/Rex Features/Shutterstock)

Romanian actress and model Madalina Diana Ghenea poses for photographers upon arrival at the premiere of the film “Killers of the Flower Moon” at the 76th international film festival, Cannes, southern France, Saturday, May 20, 2023. (Photo by Daniel Cole/AP Photo)

Apple CEO Tim Cook discusses the new iPhone 6 and iPhone 6 plus on Tuesday, September 9, 2014, in Cupertino, Calif. The iPhone 6 will have a screen measuring 4.7 inches, while the iPhone 6 Plus will be 5.5 inches. (Photo by Marcio Jose Sanchez/AP Photo)

An Economic Freedom Fighters supporter shows a mock weapons during a demonstration in Pretoria on April 12, 2017 calling for South African President Jacob Zuma to resign. Tens of thousand demonstrators took part in the march to Union Buildings, the official seat of government, which was organised on Zuma's 75th birthday and came after nationwide rallies against the president last week. Zuma's recent sacking of respected finance minister Pravin Gordhan has fanned years of public anger over government corruption scandals, record unemployment and slowing economic growth. (Photo by Marco Longari/AFP Photo)

A man stands on a jetty on the fog-shrouded Victoria Harbour Wanchai in Hong Kong, China, 22 March 2022. Fog is common in Hong Kong in spr​ingtime when the territory is affected by alternate cold and warm air. (Photo by Jerome Favre/EPA/EFE)

Boozed-out revellers donned fancy dress as they welcomed in the Bank Holiday at the Otley Run. Hundreds swarmed Leeds, UK on Saturday, March 30, 2024, as the infamous tipple mission got underway beneath blue skies and sunshine. (Photo by NB Press LTD)