Because of Australian oil prices, there are ebay companies that are buying US quarts and selling them well below our retail prices, and the OP has purchased some.
Thus his question, as the packaging is completely unfamiliar to us, not being on the shelves to compare.
What you guys pay for a gallon jug of M1 0W40 is what we pay for a litre...$100/5 litres is "special" price here.