I was just shopping for some 10w40 oil for my next change and I found Royal Purple on Autozone's site for $4.99 a quart. I cross referenced the item number and all looks good. I had to pay $13.50 in shipping for 10 qts (not available for store pickup) but it is still a really good deal for a full syn oil. I have never used Royal Purple before but I hear that it is pretty good stuff.
Engine Oil | AutoZone.com