For Prime members only, Amazon offers the Mobil 1 0W-40 Synthetic Motor Oil 1-Quart 6-Pack, model no. 96989, for $26.99 with free shipping. That's tied with our June mention and the lowest total price we could find by $7.

Also available for Prime members is the Mobil 1 5W-30 Synthetic Motor Oil 1-Quart 6-Pack, model no. 94001, for $26.99 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $9.94.) That's tied with our mention from two weeks ago and the lowest total price we could find by $7.