Posters come in many different sizes. Some of them are only the size of a sheet of paper. Others can fill part of a wall. You will even find posters for your door that fill all of it up. There are plenty of different types of posters as well that you may want to buy. Some of them are for advertising concerts and upcoming shows. Others are to advertise new businesses and even for political advertisements.
It isnt uncommon for people to display posters of their idols including rock bands and actors. For sports enthusiasts there are team posters, player posters, and even those of the cheerleaders for the team. Some of them are even in wonderful frames in order to better preserve them. Most of us are happy to put them up with some scotch tape though. Of course this makes it difficult to take them back down without tearing them.
You may want to use thumbtacks instead of tape. While they make small holes in the poster you can easily take them down and rearrange them. If you place the thumbtacks back through the same small holes you wont have any real destruction to the poster. Early posters were all in black and white. Some people have collected them from early circus...