On Sunday I was doing some errands and I get message in BMW that my diesel emissions fluid level is too low, and that in 999 miles I will not be able to turn on car. So I was thinking to go to Wal Mart where Peak DEF is $11.99 for 2.5 gallons, but I was about to pass by AutoZone. I am thinking: probably peak in AZ is $1-2 more, not worth of trip to Wal Mart. I go to AZ, and see they have Shell Rotella DEF. I just asked seller what is price out of curiosity, and he says: hmmm, I think there is some sale, let's check. Ooooops, $0.97 for 2.5 gallons! Holy [censored]! However, they only had one canister.
So on Monday I visited few more AZ's, I found two more jugs of 2.5 gallons for $0.97 each.