A National Bolivarian Police officer rescues a man who was being attacked by protesters, who then threw rocks at them, during a protest demanding food a few blocks from Miraflores presidential palace in Caracas, Venezuela, Thursday, June 2, 2016. Venezuela is seeing rising frustration with widespread food shortages and triple-digit inflation. (Photo by Fernando Llano/AP Photo)

A Hindu devotee prepares for Annakut or Goverdhan puja at Naba Brindaban temple in Kolkata on November 14, 2023. Annakut or Govardhan Puja is a Hindu festival in which devotees prepare and offer a large variety of vegetarian food to Lord Krishna as a sign of gratitude for saving them from floods as per Hindu Mythology. (Photo by Avishek Das/SOPA Images/Rex Features/Shutterstock)

The aerial view shows terraced hills at Helin village in Anqing, in eastern China's Anhui province on January 12, 2024. (Photo by AFP Photo/China Stringer Network)

Piccacho, Pokemon passes the Hero toys and is guided into the goods lift in London, United Kingdom on January 24, 2023. (Photo by Guy Bell/Alamy Live News)

Angela Griffin attends the UK premiere of Hop held at The Vue west end on March 20, 2011 in London, England.

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.

Two women lighting cigarettes on a tennis court in Essex, England circa 1930's. (Photo by Keystone View/FPG/Getty Images)

A man falls from an ox cart as he competes during an ox cart competition near U Bein bridge, in Mandalay March 22, 2015. (Photo by Soe Zeya Tun/Reuters)