All apartments and houses have many places that you can display posters:

Any wall, so long as you can see it. If you can't get far back from it, choose a poster that looks good up close.

Doors, both going into a room and inside room.

A garage or carport. The bathroom. If you like to take baths or have a hot tub, how about an interesting poster on ceiling over your tub? It may not last as long, due to humidity, but it can be fun for however long it lasts. A poster can be placed over kitchen table and covered with clear plastic. This can give an interesting look, especially with white or other simple dishes on table.

These are just a few of ways that you can display posters. Let your imagination take you further!