Amazon offers a $1 Amazon MP3 Credit for free when you download a movie or TV show. That's the best offer we've seen for Amazon MP3 credit since last month, when we saw $2 credit for free with Fandango movie tickets, and is a strong offer particularly since there is a wide selection of free titles. (Click here to view the free titles, which consist mostly of featurettes.) This offer is limited to one promotional credit per customer; you'll receive an email confirming the credit shortly after purchase. Deal ends December 31 and the credit expires January 31, 2015.