Currently at the Discovery Store, you can get this 4-disc Best of Discovery Set for only $4.97.  To make the Deal even Better use code SAVE5 and get it Free.  Just pay shipping.  I found this Deal on page 9.

The set includes:  Deadliest Catch Season 3, Planet Earth:  The Filmmaker’s Story, Man vs Wild Season 2 and Unfolding Universe.

Thanks, Frugal Coupon Living