In most cases, Amazon doesn't sell the camera/lens/etc. itself. It hooks you up with someone else who does. Amazon is a pretty ethical outfit, so they tell you up front who that is - often, you have a choice at different prices - but you have to check the real seller out as well as Amazon.

(I got a Panasonic FZ35 from 6th Ave. Photo via Amazon a couple of months ago. Price was better than any other reputable source. Worked out just fine.)