I love Pop Art Machine. It’s the perfect way to make amazing low cost art to hang on your walls. Pop Art Machine has high resolution files of millions of images that you can download and print as posters or on canvas, tee-shirts, whatever you want to do, really. And it’s free.
Go there and poke around, see what you find. Earlier today I searched for William Burroughs and found several cool galleries of his book covers from around the world, like this Japanese cover of My Education. You could print this as big as a movie poster and the resolution would still be crisp and clear.