Today is the day I've been waiting for. Autozone began a new nationwide monthly sale and included in the sale is Castrol Syntec at $4.49 per quart. When you take into account the Autozone buyer's card that after 5 purchases of $20 or more that you get a $20 credit, the net cost for 5 quarts is about $3.65 per quart. Now the ad online doesn't specify the 0W/30 weight but my store in Tulsa had it and the price was good for all weights they had in stock. I'll be buying 5 quarts at a time several times during the next 30 days. What a deal.