Six Feet Under: The Complete Series (DVD) for $74.99. Order online to confirm price and availability and select in-store pickup to save on shipping.  Here is a screenshot for your reference.  It features all 63 episodes of 5 seasons.  Most places have the set for $89 or much more.  Alternatively, each complete season DVD set is available for $17.49.

• Six Feet Under: The Complete First Season (DVD) for $17.49.  Most places have it for over $22.
• Six Feet Under: The Complete Second Season (DVD) for $17.49.  Most places have it for over $19.
• Six Feet Under: The Complete Third Season (DVD) for $17.49.  Most places have it for over $19.
• Six Feet Under: The Complete Fourth Season (DVD) for $17.49.  Most places have it for over $22.
• Six Feet Under: The Complete Fifth Season (DVD) for $17.49.  Most places have it for over $22.