If only there was some kind of machine that could search the world for these kinds of things... oh wait. Did you google "free stock images"?
I did and found:
stock xchng, getty free images, turbo photo, stock vault and a pile of others.
Maybe my sarcasmism is misplaced but, come on, google is your friend.
iStockPhoto was one I used in the past that was definitely free (I think it still is) and I think stock xchng had some free. The range wasn't as large as their paid options and they were of the more stilted variety of photos but you could get decent landscapes, people shots most of the time.