AllPosters.com is currently running a special on their site for posters. Many of their posters are almost half off, including Twilight posters and New Moon posters. This makes them only $4.98 each!
Here are just a couple of items on sale:
AllPosters.com has an entire Twilight section. They have Twilight posters, Twilight standups, framed Twilight art, Twilight shirts, and more. They also have the only New Moon movie poster that is currently out.