Was refreshing my aging memory and re-reading the thread...
No this isn't a soyboysigh posting... 
Just for giggles I thought I would see what the 55 gallon drum of Belray costs now...
Merely 1811.80 $US or $32.94/gallon.
Previous post-er reported a price on Sept. 24, 2014 of $26.9974545454/gallon or approximately $1486 for 55 gallon drum. So, the shipping costs rolled into the price or the price has gone up...at least on that one seller now offering it on Amazon.
The Amazon low price I get with free shipping is $24.30 with 9 left at that price for the 4L bottle...
Given that 4L = 1 US gallon liquid and 0.4535056 US pint liquid (7.2560896 ounces US liquid).
That 55 gallon drum is 208.1976L and dividing by 4 yields = 52.0494 4L bottles
Dividing the 1811.88 $US price by 52 yields a 4L price of about $32.84US a 4L bottle.
So, it is still cheaper to buy by the 4L bottle.
For a shop, it would be easier to store the 55 gallon drum with a leak-resistant spout that could drain the 55 gallon can cleanly. Not sure how much would be left in the drum that would be difficult to extract, same given a 4L bottle...
I've often wondered about the tiny amount left in a container... I've even seen homemade systems for draining and collecting the residual little bits into another container. One company years ago even made one where you up-ended the bottles into a oil resistant hose end that would hold 4-5 bottles to drain into a single bottle in a clamping system that had the hose leading inside the quart bottle below. It had a velcro'd elastic strap that could secure the individual bottles once up-ended and the bottom bottle threaded into a cap (apparently oil bottles mostly used the same thread pitch for their caps.)
Then, you could use the little bit left over and it could drain into the bottle until you needed it or you put another bottle in place. It is typical with today's engines to use a bit of oil between changes most every manufacturer tells us. Years ago the engines were designed not to use any, that use indicated a leak or engine problem developing. Today, you can't use that same simple diagnostic method on modern automotive engines.
The amount clinging to the bottle is small, would the greater surface area of a drum make it more difficult to extract. Then, the issue with the 55 gallon drum is it metal or plastic. For a shop, storing a drum is far more efficient space utilization/easier than 52 4L jugs.
If the drum is metal with a band clamp sealing tank lid you could potentially drain it easier by upending it into a catch pan, but it is difficult and sometimes messy and not worth the hassle or time for a shop. So, how is the drum reused or recycled?
With a plastic drum/container you can do so as well, but they tend to be more user friendly for other uses and won't rust as long as you don't puncture them. One good use I've seen large blue 55 gallon drums used for was a rainwater harvesting system to water your plants and could be sold once rinsed clean (or sold leaving the buyer to clean as appropriate.) California & some other states would not allow their disposal in that manner as the original buyer is responsible for turning over to appropriate hazardous waste unit. Most shops use the old drum as a recycle oil container for collection to their recycler.
Even in Eastern US where you get sufficient rainfall, a rainwater harvesting system is a good thing to do, Just water prices here in the Eastern US where water is more abundant haven't reached SW and W state prices. So, in eastern US and areas where there is freezing and it is viable, then you could burying the drums below the typical frost line and having a diverter gate valve to bypass the tanks in winter (so you don't have that problem of frozen tanks...
Burying them you could have a rainwater storage system that is out of sight. People in the Southwest don't hide them as often and if they are out of sight of the front of the property no-one views it as a negative that I knew. But, I didn't run with the rich people crowd. Burying the tanks gives you a evaporation resistant system as well. Houses aren't setup for the harvesting here, but rising water prices more people should be doing it as water is a resource you don't need treated and chlorinated water for washing cars, or watering plants. Just a storage system and pump system to get the water where you need it and the ability to purge the lines to protect them from freezing when winter comes, just like it would in the SW where systems are installed that see freezing temps.
Sorry for the segue...just a topic that would need addressed on what you do with the drum after use.
If you have friends with motorcycles they could pay you $33/4L to refill theirs as needed. A motorcycle club could divvy up the 55 gallon amongst members all at once. With members saving old 4L bottles for reuse. Until they punctured or recycled that bottle. Just need to mark or measure the typical height or have a metered system so you are dispensing 4L at a time or you won't have 52 4L shares if you give everyone a few ounces too much...
David
P.S. Sorry, I'm an engineer, it is my nature to think through a solutions and up and down sides and proposed end use of left over/waste materials...
55 gallons of this oil here http://www.amazon.com/Bel-Ray-EXL-Mineral-Engine-Oil/dp/B0045LCCNI
That comes out to only $26.99745454 dollars per gallon, and with free shipping to sweeten the deal!
