A kid from Sichuan provice smokes at an assistance center February 23, 2005 in Shenzhen, Guangdong Province, China. The kids, ranging in age from 7 to 16, are temporary residents of the center, one of the institutions established by China's departments of civil affairs to help and administer beggars, vagrants and juvenile delinquents, after rescission of China's compulsory detainment and relocation system. (Photo by Cancan Chu/Getty Images)

Colombian Jahn Fredy Duque, dressed as superhero “Spiderman”, performs on the streets in Bogota, Colombia on April 24, 2017. Duque hangs a white cloth 26 meters long – his cobweb – from a bridge near the international center of Bogota, where he performs in the street for a livelihood. (Photo by Raul Arboleda/AFP Photo)

Mr. Grindell Matthews with his latest invention, the new photographic gun which is the latest development in sky signs. 1933. It can throw a beam of light 15 miles into the sky. (Photo by Fox Photos)

Photographer Loes Heerink spent hours waiting on bridges in Hanoi to capture the street vendors who walked underneath. She recently launched a Kickstarter project to publish a book of these images. Here: “In Hanoi there are a lot of street vendors who roam the city with their bicycles trying to sell goods, from vegetables to flowers”. (Photo by Loes Heerink/The Guardian)

In this April 23, 2015 photo, friends Jia Haixia, left, and Jia Wenqi work to plant a tree in a field in Yeli village near Shijiazhuang city in northern China's Hebei province. For the past 13 years, Jia Wenqi, who has no arms, and Jia Haixia, who is blind, have worked together to plant and water more than 12,000 trees near their village. (Photo by Helene Franchineau/AP Photo)

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.

Supporters and opponents of Russian opposition activist and anti-corruption crusader Alexei Navalny clash during unsanctioned protest in Manezhnaya Square in Moscow, Russia, Tuesday, December 30, 2014. The unsanctioned protest came hours after Alexei Navalny was found guilty of fraud and given a suspended sentence. Navalny, who has been under house arrest since February, is accused of breaking the terms of his house arrest to attend the rally and was detained by police as he approached the site of the protest. (Photo by Ivan Sekretarev/AP Photo)

In 2002 photographer Corey Arnold left behind a poor economy in San Francisco and headed up to Alaska to try his luck at his longtime passion of fishing. Arnold, who had worked summers during college on a salmon boat in Alaska, signed onto the f/v Rollo, a crabbing boat that fishes in the dangerous Bering Sea. While working long, strenuous hours on the Rollo, Arnold often stole away with the captain’s permission to grab his camera and photograph the crew and the ship. Arnold eventually put together “Fish Work: Bering Sea”, a documentation of his seven adventurous and dicey crab seasons aboard the Rollo. (Photo by Corey Arnold)