I usually buy the 5 qt. jugs but I don't find the difference between quart and jug at WM to be anywhere near astronomical for something I do twice a year. It costs about $4 more for a 5 qt. jug of PP than buying 4 quart containers. I have a 3.5 qt. oil change which leaves me some top off oil over the course of the OCI if I need it.
If I use QSUD, it's about the same spread difference only cheaper with the individual quarts of QSUD being 75 cents cheaper than PP and the 5 qt. about $5 dollars cheaper than PP. The only oils at WM that I find comparable in price to AZ, O'Reilly's, etc. are the M1 Annual, Valvoline ME and some select ones that are $9 plus a quart. Then again, the last oil I bought was individual quarts of PP at ACE Hardware that were 50% off.