A student activist is detained during a silent protest after Thailand's election commission filed charges against a group for posting “foul and strong” comments online criticising a military-backed draft constitution, in Bangkok, Thailand April 27, 2016. (Photo by Jorge Silva/Reuters)

Sue Bunclark, 40, from Rotherham poses for a photograph besides her 1964 first generation or T1, split-screen Volkswagen Transporter Samba van in Newquay on August 6, 2014 in Cornwall, England. The van, which she and her family have owned for five years is nicknamed Sammy. The Volkswagen Transporter was first produced in 1950 and has sold over ten million units worldwide evolving through five generations of functional and practical body styles, each representing the ultimate multi-purpose vehicle of its time. To commemorate the model's 60th anniversary in the UK Volkswagen has launched a special edition of the Transporter dubbed the Sportline 60. (Photo by Matt Cardy/Getty Images)

Dhofar Region, Oman. Much of Oman is desert, but the Arabian Sea coast in the Dhofar region represents a startling difference in climate. This coastal region catches the monsoon rains, or khareef, during the summer months. Drenching rains fall primarily on the mountainous ridge that separates the lush, fertile areas along the coast from the arid interior, recharging streams, waterfalls and springs that provide plentiful water supplies in the fertile lowlands for the remainder of the year. Image taken by Landsat 5 on April 2, 2005. (Photo by USGS/NASA)

A participant of “Bread Procession of the Saint”, takes part in the ceremony in honor of Domingo de La Calzada Saint (1019-1109) who helped poor people and pilgrimage, in Santo Domingo de La Calzada, northern Spain, Wednesday, May 11, 2016. Every year during spring season, “Las Doncellas” (White Virgins), hold on their head a basket cover with white cloth while they walk past along of this old village in honor of the saint. (Photo by Alvaro Barrientos/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.

In this photo made late Saturday, August 9, 2014, in Keelung, Taiwan, a traditional Chinese dance troupe performs during a parade marking the beginning of the Chinese folklore's mid-summer's Ghost Month Festival. Fourteen days into the seventh month of the lunar calendar, August 9, in 2014, marks the traditional Chinese Ghost Month where the gates of the underworld are opened and spirits of the deceased are set free to roam the world of the living. The month long festivities are aimed to please the roaming spirits. (Photo by Chiang Ying-ying/AP Photo)

A donkey savors warming temperatures after a long winter at the zoo in Warsaw, Poland, on Wednesday, April 8, 2015. (Photo by Czarek Sokolowski/AP Photo)

A young vendor hawks food on a market in Kara in the state of Ogun, on September 23, 2015. Nigeria imposed tight movement restrictions in the restive northeast after Boko Haram bombings that killed more than 100 raised fears of fresh attacks over the Eid al-Adha festival. The military said the use of all vehicles would be banned throughout Borno state during the Muslim festival, which is known as Sallah in Nigeria and marked with two days' public holiday from Thursday. (Photo by Pius Utomi Ekpei/AFP Photo)