Amazon appears to have expanded its no-rush shipping program for the holidays, allowing Prime users to earn more than just digital music credits. No-rush shipping allows Prime customers to waive their free two-day shipping for standard 5-7 day shipping in exchange for credit toward digital purchases.

Previously, the e-tailer offered up to $3 worth of credit toward its MP3 Store for an order placed using no-rush delivery. However, that credit can now be used twoard shows and movies on Amazon's Instant Video service. Orders totaling more than $50 get $3 in credit, whereas sub-$50 purchases get $1.

By allowing users to delay some of their purchases, Amazon gains more flexibility with fulfilling orders over the busy holiday season while simultaneously encouraging Prime subscribers to try other in-house services that the company is working to expand – a tactic that few other e-tailers can employ.

We're not sure how to determine whether an item is eligible for Instant Video credit, but not everything is. The current promotion is running through December 15 and rewards earned must be redeemed by January 31, 2013. It's unclear whether the offer will revert to its previous state after December.

What we do know is that Amazon is unafraid to explore new promotions, especially when it comes to its video streaming service. Earlier this month, the company announced that it would offer Amazon Prime memberships (which includes access to thousands of videos) for $7.99 a month – the same price as Netflix and Hulu Plus. Strangely, that offer was pulled with no explanation only two weeks later.