Lots of gas cans are right around 5 gallons too; NATO 20L are 5.3 gallons, but widely available plastic ones tend to be 5 gallons as well.
Bucket lids are a PITA, but so is spilling diesel on the stairs.
I'm going to guess it was buckets. $2 each as opposed to 25-50.
I'm going to guess it was buckets. $2 each as opposed to 25-50.