The first Australian Kangaroo gold coin issued by The Perth Mint in 1989 featured an iconic bounding Red Kangaroo. Designed by Dr Stuart Devlin AO CMG, goldsmith and jeweller to Her Majesty Queen Elizabeth II, this classic creation has since been featured on the kilo release each year in the highly sought-after bullion series.

Police walk past a burning car during riots in Birmingham City Centre on August 8, 2011 in Birmingham, England. After three nights of rioting and looting in and around London, the chaos is starting to spread to other cities around Britain. (Photo by Jeff J Mitchell/Getty Images)

Iggy Azalea shares a joke with Andy Lee and Hamish Blake during Bonds 100th birthday celebration event at Cafe Sydney on August 19, 2015 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)

A photographer has created a series of paw-traits of hungry dogs pulling hilarious faces as they try and catch treats. Using a unique technique, the shots are captured at the exact moment the adorable pooches attempt to catch an airborne piece of food. The dogs appear surprised, happy, sad, confused – and sometimes even so blasé they miss the treat entirely. The images were taken by Christian Vieler, a photographer from Waltrop, Germany. Here: A labrador retriever. (Photo by Christian Vieler/Caters News)

A cloud of black smoke billows out the exhaust pipe of John Robertson's diesel dragster as he runs down the track during the 2015 NHRA Kansas Nationals, Friday, May 22, 2015, at Heartland Park in Topeka, Kan. (Photo by Chris Neal/The Topeka Capital-Journal via AP Photo)

A French soldier stands near a military combat command vehicle on display at The Defence and Security Exhibition on September 13, 2011 in London, England. ExCeL London is hosting the exhibition with hundreds of manufacturers from all over the world displaying their hardware. (Photo by Peter Macdiarmid/Getty Images)

Actress Shae Mitchell arrives at REVOLVE Desert House on April 16, 2016 in Thermal, California. (Photo by Ari Perilstein/Getty Images for A-OK Collective, LLC.)

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.