For heavy online shoppers, the greatest benefit of Amazon Prime, which costs $79 per year, is the free two-day shipping. As a side benefit, you get unlimited streaming of all their movies to your computer or HDTV. That's $17 less a year than Netflix's instant-streaming service. But Amazon's library currently has only 6,000 titles, compared with Netflix's 20,000 or so titles.
If you don't want to sign up for Amazon Prime, you can still get 48-hour on-demand rentals, which typically cost $3.99. Or you can buy the video outright, which usually costs around $15.