When I license an image for a poster, I get a handful of samples. Posters are different than my limited edition prints. Limited edition prints are produced with archival materials and can last more than a lifetime. They are signed and numbered and come with a certificate of authenticity.
Posters are printed in mass quantity and are nice, but they aren't archival, they aren't signed or numbered and they don't come with a Certificate of Authenticity. But they are nice decor options for the price.