http://www.autozone.com/images/MEDIA_ProductCatalog/m1520203_view_sz_slot_2.pdf autozone is running a promo - buy 5 qts Mobil One, get a $10 giftcard towards a future purchase...
As a note, this will not work for 2010 owners, as the 2010 requires 0W20 oil, which Mobil 1 does manufacture but is only available in 1qt quantities at autozone.com, or any autozone store. The promo mentioned above requires the purchase of a "5+ quart" (5 liter) jug. Just a note for 2010 owners who were looking to save on engine oil. As for me, I haven't found 0W20 in the 5 liter jug anywhere, but my local walmart sells the 0W30 in that size. Buying in this volume typically gives you 1 to 2 quarts free, compared to buying 5+ individual quart containers. I have a feeling, though, that sooner than later the 0W20 oil will be widely available and not so expensive.
If I am not mistaken, Mobil 1 synthetic comes in two formulations nowadays. The older well known formulation that has been quality degraded for a couple of years now, and is no better than any other GF4 oil; and a newer brand that matches the top tier Castrol and Pennzoil ACEA A1 and A5 spec'd synthetics. I usually end up finding the Pennzoil synthetic on sale after rebate for about $3/qt