Yes as the years go by these vintage posters do rise in price, but they are such unique beautiful pieces of art, they are well worth it. A great souvenir alternative.
Still one of the most unique and amazing shops in Warsaw. I first visited it in the late 70's and it still never ceases to impress. These posters make great gifts. They are getting to be pretty pricey though.
My friends & family have been thrilled to receive posters as presents, and I love shopping for them.