Exhibition poster with the work, Figures in Landscape - Figures in Landscape (1977), by American artist, Roy Lichtenstein, (1923-1997)
$55
butik.louisiana.dk/en-int/products/roy-lichtenstein-figures-in-landscape-louisiana-plakat

www.ebay.co.uk/sch/i.html?_nkw=roy+lichtenstein+poster

Totally agree so cheap for a beautiful piece!

You can get much cheaper. It's a big edition. 

Here is a set for about £600
www.abebooks.co.uk/servlet/BookDetailsPL?bi=31127645218&ref_=ps_ggl_2038407968&cm_mmc=ggl-_-UK_Shopp_RareStandard-_-product_id=bi%3A%2031127645218-_-keyword=&gclid=Cj0KCQjwvL-oBhCxARIsAHkOiu2g85Vb8S--katgTk5X7xVKv81zXZeOYkECsoqJizNUSDGgQwfx2pUaAkk-EALw_wcB

I wouldn't say so, essentially this is an open edition that was published and sold by the museum from 1966 up until a few years ago. At the last count 3,140 were printed but theoretically that could end up being higher, as nothing to stop them printing more. From what I understand they printed some in 1966, some in the 70s, some in 83, some in 2000 and some in the 2010s. They're all pretty much identical so how would people discern the date which they were printed? the Gagosian ones could quite as easily be from the last batch as the first, as the text on the back all date them as 1966. There were a very small number of signed versions of these from 1966 (they say less than 50) these of course go for much more, although there are a considerable number of fakes so beware. 

No more than a few hundred pounds. I'd call them first to check if they intend to print any more soon.