What is the summary of what you get with Amazon Prime? It is fairly pricey annual dues, if memory serves, so I have not signed up (yet).
Prime costs $79 per year, but it gets you free two day shipping, plus instant video (movies and TV shows) and you can borrow some Kindle books to read.
It may not be for everyone, especially if you don't have high speed internet or a Kindle, but just the instant video is fairly cheap, since I think NetFlix is $7.95 a month just for the streaming video.
I get quite a bit of stuff off of Amazon, so I love the free shipping. They've got a pretty good selection on the instant video (though not quite as much as NetFlix) and my wife usually "borrows" a book every month, so I consider it to be a decent value.