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.

Somali couple Mohamed Noor (L) and Huda Omar pose for a photograph at their makeshift home during their wedding ceremony in Mogadishu's Rajo camp, Somalia August 17, 2016. Having met two years ago, the pair have just married at Rajo camp, where some 400 families live. Most, like Noor's parents, came here in the early 1990s to flee famine. (Photo by Feisal Omar/Reuters)

A Police officer reacts to protestors outside the Piet Retief Magistrates court where the five accused in the shooting of the Coka brothers on the Pampoenkraal farm appeared, Mhkondo, Mpumalanga, South Africa on April 19, 2021. (Photo by Jacques Nelles)

A 69-meter-tall giant Buddha statue stands at the Wat Paknam Phasi Charoen temple on the outskirts of Bangkok on October 12, 2021. (Photo by Jack Taylor/AFP Photo)

Ten segments of the Berlin Wall, which constitute the longest stretch outside of Berlin, are seen on display in Los Angeles, California September 18, 2014. On November 9, Germany will celebrate the 25th anniversary of the fall of the Berlin Wall. To mark the event Reuters Photographers around the world captured images of segments of the wall, which are kept as monuments in many countries from Taiwan to South Africa and Costa Rica. (Photo by Mario Anzuoni/Reuters)

A woman dries chili peppers in the sun at a village in Wuyuan County, Jiangxi province, China July 21, 2017. (Photo by Reuters/China Stringer Network)

Navy midshipmen celebrate a Navy touchdown during the second half of an NCAA college football game, Saturday, December 14, 2019, in Philadelphia. Navy won 31-7. (Photo by Jonathan Newton/The Washington Post)

A man reacts as he receives 100 whippings by religious police as punishment for pre-marital sеx, outside a mosque in Jantho, Aceh province on June 5, 2020. A couple in Indonesia's conservative Aceh was publicly flogged 100 times each on June 5 after they were caught having pre-marital sеx, as one pleaded for an end to the painful punishment. Aceh is the only region in Muslim-majority Indonesia to impose Islamic law, which allows whipping for a range of charges. (Photo by Chaideer Mahyuddin/AFP Photo)