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.

Kha Tu Ngoc rests in her two- square- meter house in Ho Chi Minh City on May 2, 2018. The “micro- house” dwellings are dotted throughout Vietnam' s bustling southern hub, occupied by families clinging to postage stamp- sized plots a city developing at breakneck pace. Tucked away in winding alleys, nestled under new condo developments or sandwiched between street food stalls and shops, the tiny houses are easily missed by the unattentive passerby. (Photo by Thanh Nguyen/AFP Photo)

Ayesha Farooq, 26, Pakistan's only female war-ready fighter pilot watches an airforce jet about to take off at Mushaf base in Sargodha, north Pakistan June 7, 2013. Farooq, from Punjab province's historic city of Bahawalpur, is one of 19 women who have become pilots in the Pakistan Air Force over the last decade – there are five other female fighter pilots, but they have yet to take the final tests to qualify for combat. A growing number of women have joined Pakistan's defence forces in recent years as attitudes towards women change. (Photo by Zohra Bensemra/Reuters)

A British space-exploration company has revealed its aim to fly the public to the moon from 2015 – providing they have £100m for a ticket.

Photo: Jenn Sander from Red Robin PR, wearing a spacesuit once worn by US Astronaut Peggy Whitson, sits inside a re-entry capsule owned by Excalibur Almaz outside the Queen Elizabeth II Centre on June 19, 2012 in London, England. The company today announced their plan to fly people to the moon on what is the 40th anniversary year of the Apollo 17 moon landing. (Photo by Rosie Hallam)

“Microscope images forge an extraordinary bond between science and art, said Hidenao Tsuchiya, Olympus America's Vice President and General Manager for the Scientific Equipment Group. We founded this competition to focus on the fascinating stories coming out of today's life science research laboratories. The thousands of images that people have shared with the competition over the years reflect some of the most exciting work going on in research today – work that can help shed light on the living universe and ultimately save lives. We look at BioScapes and these beautiful images as sources of education and inspiration to us and the world”. – OlympusBioScapes

Photo: Pretarsus of the third leg of a female drone fly (Eristalis tenax), ventral view, by Dr. Jan Michels, Institute of Zoology, Christian-Albrechts-University of Kiel, Germany. (Photo by Olympus BioScapes)

Tokyo Rainbow Pride 2015, at Yoyogi park-Shibuya, on April 26, 2015. Some 3,000 lesbian, gay, bisexual and transgender people paraded through Tokyo’s Shibuya district Sunday afternoon to demonstrate their hope that Japanese society will continue to forge ahead with recent moves to embrace equality and diversity. In a nation where prejudice against sexual minorities persists, the annual Tokyo Rainbow Pride parade has sought to counter the trend by openly spotlighting LGBT residents and spreading their voices. But this year, LGBT participants and proponents seemed particularly joyous, emboldened by what they see as a blossoming of LGBT-friendly moves by municipalities and companies. (Photo by Yoshiaki Miura)

Li Tingting, second from right, laughs as she is lifted off the ground by her wife Teresa Xu, right, outside of a beauty salon where the two were preparing for their wedding as clerks from an adjacent shop look on in Beijing, Thursday, July 2, 2015. Li, a 25-year-old prominent women's rights activist who was released from detention in April, held the wedding ceremony with her partner Teresa on Thursday and announced their marriage in an effort to push for LGBT (lesbian, gay, bisexual, and transgender) rights in China. (Photo by Mark Schiefelbein/AP Photo)

In this Monday, June 15, 2015 photo, Ahmad Abu Jereda, 16, carries Max, the male lion cub, as he passes by Palestinians at the main garden in Gaza City, in the northern Gaza Strip. A pair of lion cubs are stuck at a Gaza-Israel border crossing en route to a Jordan animal sanctuary, after being kept for a year by a family in crowded Gaza. Saduldin al-Jamal had bought the cubs from the Gaza zoo, hit during last summer's Israel-Hamas war. His family would take them to parks or the beach and children – those brave enough – would come up to pet them. (Photo by Adel Hana/AP Photo)