[sennix]

Amazon.com
Pennzoil 550040834 Platinum Euro SAE 5W-40 Full Synthetic Motor Oil (1 Quart) for $6.98 / Quart.
(Limit 6 per order, per person ...?! I couldn't order more ... tried couple times).

Walmart listed it for 5-min and took it down for wrong price. Amazon price seems auto-match, but then got stuck unfixed.

AdvanceAutoParts.com
Castrol EDGE 0W-40 Full Synthetic Motor Oil (1 Quart) for $5.50 / Quart

Castrol EDGE 5W-40 USA Full Synthetic Motor Oil (1 Quart) for $5.50 / Quart
(The image on website shows old edition and LL-98 Approved; however, part number 06249 is now in new edition package, and is BMW LL-01 Approved).

Tip on AdvanceAutoParts: Order online, Pick up in store. Get 5% cashback via Upromise.

Have fun stocking up. :-). Price is valid as of 03/18/2017.