If you’re stil on the fence about ponying up the $79 a year for Amazon Prime, the company hopes that a new deal with MGM is the kind of motivation you’re looking for.

Film fans with Amazon Prime memberships will now be able to enjoy hundreds of classic movies and TV episodes courtesy of a deal between Amazon and Metro-Goldwyn-Mayer Studios. The movies will appear as Prime Instant Video offerings – which means that Prime members can watch them at no additional cost.

“Our customers tell us they love having tons of movies and TV shows to choose from, which is why we are focused on adding even more titles to our already extensive Prime Instant Video library,” said Brad Beale, director of digital video content acquisition for Amazon, and “MGM offers one of the most distinguished catalogs in all of Hollywood.”

The deal brings films like Silence of the Lambs, The Terminator, Dances with Wolves, and Rain Man to Prime Instant video. Unfortunately, customers won’t receive all of the new additions at once – as they’ll be rolling out over the course of 2012.

These MGM additions bring the grand total to 18,000 movies and TV episodes that are available for “free” through Prime Instant video. Just last month, Amazon inked a similar deal with Paramount Pictures that brought other big-name films like Braveheart and Forrest Gump to the service. Plus, Xbox 360 users will be able to enjoy these classic films through a newly launched app.