People take pictures with their mobile phone of a scale model of a dinosaur displayed in front of La Sapienza University headquarters in Rome April 10, 2015. The realistic reproductions of dinosaurs are part of the “Dinosaurs in the flesh, science and art bring to life the rulers of a lost world” exhibition. (Photo by Alessandro Bianchi/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.

A man drinks a Frucola as a policeman chases demonstrators during a protest against Chile's government in Santiago, Chile on December 4, 2019. (Photo by Goran Tomasevic/Reuters)

A girl reacts while getting a nasal swab sample at a testing and screening facility for the new coronavirus in a hospital in Karachi, Pakistan, Friday, July 17, 2020. (Photo by Fareed Khan/AP Photo)

These girls are all smiles as they celebrate surviving A-level results day in Birmingham, England on August 15, 2019. The A Level is a subject-based qualification conferred as part of the General Certificate of Education, as well as a school leaving qualification offered by the educational bodies in the United Kingdom. (Photo by SnapperSK/SnapperMS)

Tom Kaulitz and Heidi Klum attend Heidi Klum's 20th Annual Halloween Party presented by Amazon Prime Video and SVEDKA Vodka at Cathédrale New York on October 31, 2019 in New York City. (Photo by Craig Barritt/Getty Images for SVEDKA)

“Coming back home at 5am sunrise, I was just beginning to digest the grand event I was lucky to witness and cover: the wedding of the grandson of one of the most influential spiritual leaders in Israel’s ultra-Orthodox community...”. – Ronen Zvulun via Reuters. Photo: Ultra-orthodox Jewish wedding in Israel. Tens of thousands of Ultra-Orthodox Jews of the Belz Hasidic dynasty gather at the wedding ceremony of Rabbi Shalom Rokach in Kiryat Belz, in Jerusalem, on May 21, 2013. Around 25,000 ultra-orthodox Jews took part, making it one of the biggest weddings of the past few years. (Photo by Gil Cohen)