i recently purchased 5 of the 11x17 posters along with 5 custom frames. i purchased all of the posters at www.ebay.com. i used the site i mentioned as a reference for prices. i decided i would not bid more than 20% below what the website listed. Got most of the posters for between 10 and 15 dollars a pop. still looking for the feynman poster but im not sure they made it in 11x17 dimensions.
redlightrunner is VERY overpriced. they are asking for several hundred dollars for posters that are selling for 10 to 20 dollars everywhere else. i find price inflation that is an order of magnitude greater than the accepted price quite shocking. but hey if people will pay then to each his own!