Amazon.com is currently offering a free $4 credit towards anything in their Video on Demand catalog, which includes thousands of movies and shows. Enter code AVODGIFT. The credit is good until 11:59p.m. January 3rd, 2010 (PST).
1.) Visit Amazon Video On Demand promotion page
2.) Enter promotional code: AVODGIFT
3.) Click the button on the top of the page and enter your code. Your credit will be automatically applied to your account.
4.) Choose from the list of TV shows eligible for this discount