Out of curiosity, I called a local oil distributor. He can get oil in a 55 gal drum, but he said delivery to his warehouse could only be done "once they fill a complete semi trailer", meaning that there was no regular delivery of the stuff and he recommended a 30 gallon barrel, which he had on hand. Price for a 30 gallon 10W-30 drum was 350.00, plus the deposit on the drum, which was $20. Then there is the cost of the spigot pump or valve. (Spigot pump allows vertical storage. A bung valve allows horizontal storage) There is also the cost to deliver the stuff, (if needed) as you just don't throw in a 55 or 30 gallon drum in your Geo Metro.
This was for plain-jane SM 10W-30, premium named oils were higher.
One FYI here. This retailer still puts a deposit on the barrel. Most of the other local retailers do not. If you have a deposit barrel in your possession and the company suddenly decides to sell oil using the no-deposit barrel, you have lost your barrel deposit.
Bottom line: At the bare minimum, this stuff is $11.67 a gallon. Buy it for convenience, not to save money.