A woman lies injured after an incident on Westminster Bridge in London on Wednesday, March 22, 2017. A police officer has been stabbed near to the British Parliament and the alleged assailant shot by armed police. Scotland Yard report they have been called to an incident on Westminster Bridge where several people have been injured by a car. (Photo by Toby Melville/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 1934 Packard Chassis Coachbuilt Body is displayed during The Quail, A Motorsports Gathering, in Carmel, California, U.S. August 19, 2016. The Pebble Beach Concours d'Elegance is an automotive charitable event held each year on the Pebble Beach Golf Links in Pebble Beach, California, considered the most prestigious event of its kind. It is the finale of Monterey Car Week held in August every year. (Photo by Michael Fiala/Reuters/Courtesy of The Revs Institute)

A photographer with a passion for wild animals was able to get up close and personal with one of nature’s deadliest creatures. Alex Suh has traveled to Mexico’s Banco Chinchorro reef twice in the past three years to get into the waters and capture the crocodiles in their natural habitat after an invitation from Yucatan Dive Trek. (Photo by Alex Suh/Caters News Agency)

The pictures were taken by photographer Jorge Farfan and reveal the spiders’ bright colours. The 33-year-old captured the jumping, wolf, and lycosa spiders in a riverside field near his home in La Coruna, Spain. (Photo by Jorge Fardels/Solent News/SIPA Press)

32 year old Mahada Khatum repairs a fishing net outside her home in the Shamalapur Rohingya refugee settlement on April 11, 2014 in Chittagong district, Bangladesh. Some years ago she escaped violence and discrimination from the Zomgara Baharchara village in the Meherulla district of Myanmar. (Photo by Getty Images/Stringer)

People with red hair from all over the world gather on “Roodharigendag” (Redhead Day) in Breda, The Netherlands, 07 September 2014. The Redhead Day is celebrated annually at the old Dutch city on the first weekend in September. It offers cultural events, music, a picnic, a fashion show and art exhibitions from and for the red haired community. (Photo by Arie Kievit/EPA)

Ryan Randall plays the bagpipes outside a polling station in Edinburgh, Scotland September 18, 2014. Polling in the referendum on Scottish independence began on Thursday morning, as Scotland votes whether or not to end the 307-year-old union with the rest of the United Kingdom. (Photo by Paul Hackett/Reuters)