Belarus' Aryna Sabalenka poses with the 2023 Australian Open winner's trophy in Royal Botanic Garden in Melbourne on January 29, 2023, following her victory over Kazakhstan's Elena Rybakina in the women's singles final of the tennis tournament. (Photo by Carl Recine/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 biker carrying huge bags of recyclables travels on a street outside Phnom Penh, Cambodia on Saturday, March 27, 2021. (Photo by Heng Sinith/AP Photo)

Participants play in the mud as they plant rice samplings during National Paddy Day, also called Asar Pandra, that marks the commencement of rice crop planting in paddy fields as monsoon season arrives, in Dhading, Nepal, June 30, 2019. (Photo by Navesh Chitrakar/Reuters)

A young trumpeter joins the Anglican Church band as the coffin of late Archbishop Emeritus Desmond Tutu arrives outside the St. George's Cathedral in Cape Town, South Africa, 31 December 2021. The anti-apartheid leader and Nobel Peace Prize laureate, who was a key figure in the dismantling of apartheid, died on 26 December 2021 at the age of 90. A full state funeral will be held on 01 January 2022. (Photo by Nic Bothma/EPA/EFE)

Sеx worker Geraldine wearing cat make-up sits on her usual corner as she waits for clients outside the Revolution subway station, in Mexico City, Saturday, March 13, 2021. Geraldine, 30, a sеx worker since age 15, says many of her regular clients have stopped coming amid the coronavirus pandemic and that seeing new clients presents new health and security risks. She is most concerned about the risk of bringing COVID-19 home to her partner, who has diabetes. (Photo by Rebecca Blackwell/AP Photo)

An ascetic performs yoga at his makeshift tent near the banks of Sangam -the confluence of the Ganges, Yamuna and mythical Saraswati river during the Magh Mela festival in Allahabad on January 28, 2022. (Photo by Sanjay Kanojia/AFP Photo)

A topless activist of women's rights group FEMEN tries to break a segment of the Berlin wall which is on display outside the German embassy, during a protest against EU visa regime for Ukrainian citizens in Kiev, Ukraine, November 24, 2016. (Photo by Valentyn Ogirenko/Reuters)